Timelike single-logarithm-resummed splitting functions

Energy Technology Data Exchange (ETDEWEB)

Albino, S.; Bolzoni, P.; Kniehl, B.A. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Kotikov, A.V. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Joint Inst. of Nuclear Research, Moscow (Russian Federation). Bogoliubov Lab. of Theoretical Physics

2011-08-15

We calculate the single logarithmic contributions to the quark singlet and gluon matrix of timelike splitting functions at all orders in the modified minimal-subtraction (MS) scheme. We fix two of the degrees of freedom of this matrix from the analogous results in the massive-gluon regularization scheme by using the relation between that scheme and the MS scheme. We determine this scheme transformation from the double logarithmic contributions to the timelike splitting functions and the coefficient functions of inclusive particle production in e{sup +}e{sup -} annihilation now available in both schemes. The remaining two degrees of freedom are fixed by reasonable physical assumptions. The results agree with the fixed-order results at next-to-next-to-leading order in the literature. (orig.)

Morse theory on timelike and causal curves

International Nuclear Information System (INIS)

Everson, J.; Talbot, C.J.

1976-01-01

It is shown that the set of timelike curves in a globally hyperbolic space-time manifold can be given the structure of a Hilbert manifold under a suitable definition of 'timelike.' The causal curves are the topological closure of this manifold. The Lorentzian energy (corresponding to Milnor's energy, except that the Lorentzian inner product is used) is shown to be a Morse function for the space of causal curves. A fixed end point index theorem is obtained in which a lower bound for the index of the Hessian of the Lorentzian energy is given in terms of the sum of the orders of the conjugate points between the end points. (author)

Space- and time-like superselection rules in conformal quantum field theory

International Nuclear Information System (INIS)

Schroer, Bert

2000-11-01

In conformally invariant quantum field theories one encounters besides the standard DHR superselection theory based on spacelike (Einstein-causal) commutation relations and their Haag duality another timelike (Huygens) based superselection structure. Whereas the DHR theory based on spacelike causality of observables confirmed the Lagrangian internal symmetry picture on the level of the physical principles of local quantum physics, the attempts to understand the timelike based superselection charges associated with the center of the conformal covering group in terms of timelike localized charges lead to a more dynamical role of charges outside the DR theorem and even outside the Coleman-Mandula setting. The ensuing plektonic timelike structure of conformal theories explains the spectrum of the anomalous scale dimensions in terms of admissible braid group representations, similar to the explanation of the possible anomalous spin spectrum expected from the extension of the DHR theory to stringlike d=1+2 plektonic fields. (author)

Matrix model and time-like linear dila ton matter

International Nuclear Information System (INIS)

Takayanagi, Tadashi

2004-01-01

We consider a matrix model description of the 2d string theory whose matter part is given by a time-like linear dilaton CFT. This is equivalent to the c=1 matrix model with a deformed, but very simple Fermi surface. Indeed, after a Lorentz transformation, the corresponding 2d spacetime is a conventional linear dila ton background with a time-dependent tachyon field. We show that the tree level scattering amplitudes in the matrix model perfectly agree with those computed in the world-sheet theory. The classical trajectories of fermions correspond to the decaying D-boranes in the time-like linear dilaton CFT. We also discuss the ground ring structure. Furthermore, we study the properties of the time-like Liouville theory by applying this matrix model description. We find that its ground ring structure is very similar to that of the minimal string. (author)

Mayday system infiniti communicator; Kinkyu tsuho system Infiniti Communicator

Energy Technology Data Exchange (ETDEWEB)

Iijima, Y.; Ito, T.; Isono, Y.; Sekiya, M.; Koizumi, H.; Miyazaki, S.; Kishore, A.; Lawor, D. [Nissan Motor Co. Ltd., Tokyo (Japan)

1999-02-01

To respond to emergency situations associated with vehicle accidents and mechanical problems on the road, a novel emergency communication system, which combines vehicle electronics, GPS and communication systems, has been developed and is contributing to safety in the U.S. In addition to emergency communication, other features including theft protection, security, convenience features, etc. are to be added to this system in the future. An emergency communication system, `The Infiniti Communicator`, which began its service in March 1998 under such a market trend, is explained in this report. (author)

Nucleon electromagnetic structure studies in the spacelike and timelike regions

International Nuclear Information System (INIS)

Guttmann, Julia

2013-01-01

The thesis investigates the nucleon structure probed by the electromagnetic interaction. One of the most basic observables, reflecting the electromagnetic structure of the nucleon, are the form factors, which have been studied by means of elastic electron-proton scattering with ever increasing precision for several decades. In the timelike region, corresponding with the proton-antiproton annihilation into a electron-positron pair, the present experimental information is much less accurate. However, in the near future high-precision form factor measurements are planned. About 50 years after the first pioneering measurements of the electromagnetic form factors, polarization experiments stirred up the field since the results were found to be in striking contradiction to the findings of previous form factor investigations from unpolarized measurements. Triggered by the conflicting results, a whole new field studying the influence of two-photon exchange corrections to elastic electron-proton scattering emerged, which appeared as the most likely explanation of the discrepancy. The main part of this thesis deals with theoretical studies of two-photon exchange, which is investigated particularly with regard to form factor measurements in the spacelike as well as in the timelike region. An extraction of the two-photon amplitudes in the spacelike region through a combined analysis using the results of unpolarized cross section measurements and polarization experiments is presented. Furthermore, predictions of the two-photon exchange effects on the e + p/e - p cross section ratio are given for several new experiments, which are currently ongoing. The two-photon exchange corrections are also investigated in the timelike region in the process p anti p → e + e - by means of two factorization approaches. These corrections are found to be smaller than those obtained for the spacelike scattering process. The influence of the two-photon exchange corrections on cross section

Ambitwistor strings at null infinity and (subleading) soft limits

International Nuclear Information System (INIS)

Geyer, Yvonne; Lipstein, Arthur E; Mason, Lionel

2015-01-01

The relationship between BMS symmetries at null infinity and Weinberg's soft theorems for gravitons and photons together with their subleading extensions are developed using ambitwistor string theory. Ambitwistor space is the phase space of complex null geodesics in complexified space-time. We show how it can be canonically identified with the cotangent bundle of complexified null infinity. BMS symmetries of null infinity lift to give a Hamiltonian action on ambitwistor space, both in general dimension and in its twistorial four-dimensional representation. General vertex operators arise from Hamiltonians generating diffeomorphisms of ambitwistor space that determine the scattering from past to future null infinity. When a momentum eigenstate goes soft, the diffeomorphism defined by its leading and its subleading part are extended BMS generators realized in the world sheet conformal field theory of the ambitwistor string. More generally, this gives an explicit perturbative correspondence between the scattering of null geodesics and that of the gravitational field via ambitwistor string theory. (paper)

Nucleon electromagnetic structure studies in the spacelike and timelike regions

Energy Technology Data Exchange (ETDEWEB)

Guttmann, Julia

2013-07-23

The thesis investigates the nucleon structure probed by the electromagnetic interaction. One of the most basic observables, reflecting the electromagnetic structure of the nucleon, are the form factors, which have been studied by means of elastic electron-proton scattering with ever increasing precision for several decades. In the timelike region, corresponding with the proton-antiproton annihilation into a electron-positron pair, the present experimental information is much less accurate. However, in the near future high-precision form factor measurements are planned. About 50 years after the first pioneering measurements of the electromagnetic form factors, polarization experiments stirred up the field since the results were found to be in striking contradiction to the findings of previous form factor investigations from unpolarized measurements. Triggered by the conflicting results, a whole new field studying the influence of two-photon exchange corrections to elastic electron-proton scattering emerged, which appeared as the most likely explanation of the discrepancy. The main part of this thesis deals with theoretical studies of two-photon exchange, which is investigated particularly with regard to form factor measurements in the spacelike as well as in the timelike region. An extraction of the two-photon amplitudes in the spacelike region through a combined analysis using the results of unpolarized cross section measurements and polarization experiments is presented. Furthermore, predictions of the two-photon exchange effects on the e{sup +}p/e{sup -}p cross section ratio are given for several new experiments, which are currently ongoing. The two-photon exchange corrections are also investigated in the timelike region in the process p anti p → e{sup +}e{sup -} by means of two factorization approaches. These corrections are found to be smaller than those obtained for the spacelike scattering process. The influence of the two-photon exchange corrections on

Conformal Infinity

OpenAIRE

Frauendiener, J?rg

2000-01-01

The notion of conformal infinity has a long history within the research in Einstein's theory of gravity. Today, 'conformal infinity' is related to almost all other branches of research in general relativity, from quantisation procedures to abstract mathematical issues to numerical applications. This review article attempts to show how this concept gradually and inevitably evolved from physical issues, namely the need to understand gravitational radiation and isolated systems within the theory...

Conformal Infinity

Directory of Open Access Journals (Sweden)

Frauendiener Jörg

2000-08-01

Full Text Available The notion of conformal infinity has a long history within the research in Einstein's theory of gravity. Today, ``conformal infinity'' is related with almost all other branches of research in general relativity, from quantisation procedures to abstract mathematical issues to numerical applications. This review article attempts to show how this concept gradually and inevitably evolved out of physical issues, namely the need to understand gravitational radiation and isolated systems within the theory of gravitation and how it lends itself very naturally to solve radiation problems in numerical relativity. The fundamental concept of null-infinity is introduced. Friedrich's regular conformal field equations are presented and various initial value problems for them are discussed. Finally, it is shown that the conformal field equations provide a very powerful method within numerical relativity to study global problems such as gravitational wave propagation and detection.

Conformal Infinity.

Science.gov (United States)

Frauendiener, Jörg

2004-01-01

The notion of conformal infinity has a long history within the research in Einstein's theory of gravity. Today, "conformal infinity" is related to almost all other branches of research in general relativity, from quantisation procedures to abstract mathematical issues to numerical applications. This review article attempts to show how this concept gradually and inevitably evolved from physical issues, namely the need to understand gravitational radiation and isolated systems within the theory of gravitation, and how it lends itself very naturally to the solution of radiation problems in numerical relativity. The fundamental concept of null-infinity is introduced. Friedrich's regular conformal field equations are presented and various initial value problems for them are discussed. Finally, it is shown that the conformal field equations provide a very powerful method within numerical relativity to study global problems such as gravitational wave propagation and detection.

Spatial and null infinity via advanced and retarded conformal factors

International Nuclear Information System (INIS)

Hayward, Sean A.

2003-01-01

A new approach to space-time asymptotics is presented, refining Penrose's idea of conformal transformations with infinity represented by the conformal boundary of space-time. It is proposed that the Penrose conformal factor be a product of advanced and retarded conformal factors, which asymptotically relate physical and conformal null coordinates and vanish at future and past null infinity respectively. A refined definition of asymptotic flatness at both spatial and null infinity is given, including that the conformal boundary is locally a light cone, with spatial infinity as the vertex. It is shown how to choose the conformal factors so that this asymptotic light cone is locally a metric light cone. The theory is implemented in the spin-coefficient (or null-tetrad) formalism by a joint transformation of the spin-metric and spin-basis (or metric and tetrad). Asymptotic regularity conditions are proposed, based on the conformal boundary locally being a smoothly embedded metric light cone. These conditions ensure that the Bondi-Sachs energy-flux integrals of ingoing and outgoing gravitational radiation decay at spatial infinity such that the total radiated energy is finite, and that the Bondi-Sachs energy-momentum has a unique limit at spatial infinity, coinciding with the uniquely rendered ADM energy-momentum

Covariant description of kinetic freeze-out through a finite time-like layer

International Nuclear Information System (INIS)

Molnar, E; Csernai, L P; Magas, V K; Lazar, Zs I; NyIri, A; Tamosiunas, K

2007-01-01

The freeze-out (FO) problem is addressed for a covariant FO probability and a finite FO layer with a time-like normal vector continuing the line of studies introduced in Molnar et al (2006 Phys. Rev. C 74 024907). The resulting post-FO momentum distribution functions are presented and discussed. We show that in general the post-FO distributions are non-thermal and asymmetric distributions even for time-like FO situations

Time asymmetric spacetimes near null and spatial infinity: I. Expansions of developments of conformally flat data

International Nuclear Information System (INIS)

Kroon, Juan Antonio Valiente

2004-01-01

The conformal Einstein equations and the representation of spatial infinity as a cylinder introduced by Friedrich are used to analyse the behaviour of the gravitational field near null and spatial infinity for the development of data which are asymptotically Euclidean, conformally flat and time asymmetric. Our analysis allows for initial data whose second fundamental form is more general than the one given by the standard Bowen-York ansatz. The conformal Einstein equations imply, upon evaluation on the cylinder at spatial infinity, a hierarchy of transport equations which can be used to calculate asymptotic expansions for the gravitational field in a recursive way. It is found that the solutions to these transport equations develop logarithmic divergences at the critical sets where null infinity meets spatial infinity. Associated with these, there is a series of quantities expressible in terms of the initial data (obstructions), which if zero, preclude the appearance of some of the logarithmic divergences. The obstructions are, in general, time asymmetric. That is, the obstructions at the intersection of future null infinity with spatial infinity are in general different from those obtained at the intersection of past null infinity with spatial infinity. The latter allows for the possibility of having spacetimes where future and past null infinity have different degrees of smoothness. Finally, it is shown that if both sets of obstructions vanish up to a certain order, then the initial data have to be asymptotically Schwarzschildean in a certain sense

Closed timelike curves in asymmetrically warped brane universes

Science.gov (United States)

Päs, Heinrich; Pakvasa, Sandip; Dent, James; Weiler, Thomas J.

2009-08-01

In asymmetrically-warped spacetimes different warp factors are assigned to space and to time. We discuss causality properties of these warped brane universes and argue that scenarios with two extra dimensions may allow for timelike curves which can be closed via paths in the extra-dimensional bulk. In particular, necessary and sufficient conditions on the metric for the existence of closed timelike curves are presented. We find a six-dimensional warped metric which satisfies the CTC conditions, and where the null, weak and dominant energy conditions are satisfied on the brane (although only the former remains satisfied in the bulk). Such scenarios are interesting, since they open the possibility of experimentally testing the chronology protection conjecture by manipulating on our brane initial conditions of gravitons or hypothetical gauge-singlet fermions (“sterile neutrinos”) which then propagate in the extra dimensions.

Timelike naked singularity

International Nuclear Information System (INIS)

Goswami, Rituparno; Joshi, Pankaj S.; Vaz, Cenalo; Witten, Louis

2004-01-01

We construct a class of spherically symmetric collapse models in which a naked singularity may develop as the end state of collapse. The matter distribution considered has negative radial and tangential pressures, but the weak energy condition is obeyed throughout. The singularity forms at the center of the collapsing cloud and continues to be visible for a finite time. The duration of visibility depends on the nature of energy distribution. Hence the causal structure of the resulting singularity depends on the nature of the mass function chosen for the cloud. We present a general model in which the naked singularity formed is timelike, neither pointlike nor null. Our work represents a step toward clarifying the necessary conditions for the validity of the Cosmic Censorship Conjecture

Conformal Infinity

Directory of Open Access Journals (Sweden)

Frauendiener Jörg

2004-01-01

Full Text Available The notion of conformal infinity has a long history within the research in Einstein's theory of gravity. Today, 'conformal infinity' is related to almost all other branches of research in general relativity, from quantisation procedures to abstract mathematical issues to numerical applications. This review article attempts to show how this concept gradually and inevitably evolved from physical issues, namely the need to understand gravitational radiation and isolated systems within the theory of gravitation, and how it lends itself very naturally to the solution of radiation problems in numerical relativity. The fundamental concept of null-infinity is introduced. Friedrich's regular conformal field equations are presented and various initial value problems for them are discussed. Finally, it is shown that the conformal field equations provide a very powerful method within numerical relativity to study global problems such as gravitational wave propagation and detection.

Ways of Infinity

Directory of Open Access Journals (Sweden)

Salanskis Jean-Michel

2016-03-01

Full Text Available The paper discusses analogies between the way in which infinity is understood and dealt with in mathematics and in Jewish tradition. It begins with recalling the classical debate about infinity in the field of the foundations of mathematics. Reading an important paper by A. Robinson, we come to the conclusion that mathematicians work “as if” infinite totalities existed. They do so by following the rules of their formalized discourse which, at least if it refers to anything at all, also refers to such totalities. The paper describes how, according to Jewish tradition, infinity is also not theological: instead of thinking that they own some infinite being or relate to it, observant Jews follow Jewish law.

Single-Spin Polarization Effects and the Determination of Timelike Proton Form Factors

Energy Technology Data Exchange (ETDEWEB)

Brodsky, S

2003-10-24

We show that measurements of the proton's polarization in e{sup +}e{sup -} {yields} p{bar p} strongly discriminate between analytic forms of models which fit the proton form factors in the spacelike region. In particular, the single-spin asymmetry normal to the scattering plane measures the relative phase difference between the timelike G{sub E} and G{sub M} form factors. The expected proton polarization in the timelike region is large, of order of several tens of percent.

Towards three-loop QCD corrections to the time-like splitting functions

International Nuclear Information System (INIS)

Gituliar, O.; Moch, S.

2015-05-01

We report on the status of a direct computation of the time-like splitting functions at next-to-next-to-leading order in QCD. Time-like splitting functions govern the collinear kinematics of inclusive hadron production and the evolution of the parton fragmentation distributions. Current knowledge about them at three loops has been inferred by means of crossing symmetry from their related space-like counterparts, which has left certain parts of the off-diagonal quark-gluon splitting function undetermined. This motivates an independent calculation from first principles. We review the tools and methods which are applied to attack the problem.

Infinity a very short introduction

CERN Document Server

Stewart, Ian

2017-01-01

Infinity is an intriguing topic, with connections to religion, philosophy, metaphysics, logic, and physics as well as mathematics. Its history goes back to ancient times, with especially important contributions from Euclid, Aristotle, Eudoxus, and Archimedes. The infinitely large (infinite) is intimately related to the infinitely small (infinitesimal). Cosmologists consider sweeping questions about whether space and time are infinite. Philosophers and mathematicians ranging from Zeno to Russell have posed numerous paradoxes about infinity and infinitesimals. Many vital areas of mathematics rest upon some version of infinity. The most obvious, and the first context in which major new techniques depended on formulating infinite processes, is calculus. But there are many others, for example Fourier analysis and fractals. In this Very Short Introduction, Ian Stewart discusses infinity in mathematics while also drawing in the various other aspects of infinity and explaining some of the major problems and insights ...

How are Concepts of Infinity Acquired?

Directory of Open Access Journals (Sweden)

Trzęsicki Kazimierz

2015-03-01

Full Text Available Concepts of infinity have been subjects of dispute since antiquity. The main problems of this paper are: is the mind able to acquire a concept of infinity? and: how are concepts of infinity acquired? The aim of this paper is neither to say what the meanings of the word “infinity” are nor what infinity is and whether it exists. However, those questions will be mentioned, but only in necessary extent.

Infinity properads and infinity wheeled properads

CERN Document Server

Hackney, Philip; Yau, Donald

2015-01-01

The topic of this book sits at the interface of the theory of higher categories (in the guise of (∞,1)-categories) and the theory of properads. Properads are devices more general than operads, and enable one to encode bialgebraic, rather than just (co)algebraic, structures.   The text extends both the Joyal-Lurie approach to higher categories and the Cisinski-Moerdijk-Weiss approach to higher operads, and provides a foundation for a broad study of the homotopy theory of properads. This work also serves as a complete guide to the generalised graphs which are pervasive in the study of operads and properads. A preliminary list of potential applications and extensions comprises the final chapter.   Infinity Properads and Infinity Wheeled Properads is written for mathematicians in the fields of topology, algebra, category theory, and related areas. It is written roughly at the second year graduate level, and assumes a basic knowledge of category theory.

Form factors and QCD in spacelike and timelike region

International Nuclear Information System (INIS)

A.P. Bakulev; A.V. Radyushkin; N.G. Stefanis

2000-01-01

The authors analyze the basic hard exclusive processes: πγ * γ-transition, pion and nucleon electromagnetic form factors, and discuss the analytic continuation of QCD formulas from the spacelike q 2 2 > 0 of the relevant momentum transfers. They describe the construction of the timelike version of the coupling constant α s . They show that due to the analytic continuation of the collinear logarithms each eigenfunction of the evolution equation acquires a phase factor and investigate the resulting interference effects which are shown to be very small. They found no sources for the K-factor-type enhancements in the perturbative QCD contribution to the hadronic form factors. To study the soft part of the pion electromagnetic form factor, they use a QCD sum rule inspired model and show that there are non-canceling Sudakov double logarithms which result in a K-factor-type enhancement in the timelike region

Form factors and QCD in spacelike and timelike regions

International Nuclear Information System (INIS)

Bakulev, A. P.; Radyushkin, A. V.; Stefanis, N. G.

2000-01-01

We analyze the basic hard exclusive processes, the πγ * γ-transition and the pion and nucleon electromagnetic form factors, and discuss the analytic continuation of QCD formulas from the spacelike q 2 2 >0 of the relevant momentum transfers. We describe the construction of the timelike version of the coupling constant α s . We show that due to the analytic continuation of the collinear logarithms, each eigenfunction of the evolution equation acquires a phase factor and investigate the resulting interference effects which are shown to be very small. We find no sources for the K-factor-type enhancements in the perturbative QCD contribution to the hadronic form factors. To study the soft part of the pion electromagnetic form factor, we use a QCD sum rule inspired model and show that there are noncanceling Sudakov double logarithms which result in a K-factor-type enhancement in the timelike region

Kaon transverse charge density from space- and timelike data

Science.gov (United States)

Mecholsky, N. A.; Meija-Ott, J.; Carmignotto, M.; Horn, T.; Miller, G. A.; Pegg, I. L.

2017-12-01

We used the world data on the kaon form factor to extract the transverse kaon charge density using a dispersion integral of the imaginary part of the kaon form factor in the timelike region. Our analysis includes recent data from e+e- annihiliation measurements extending the kinematic reach of the data into the region of high momentum transfers conjugate to the region of short transverse distances. To calculate the transverse density we created a superset of both timelike and spacelike data and developed an empirical parameterization of the kaon form factor. The spacelike set includes two new data points we extracted from existing cross section data. We estimate the uncertainty on the resulting transverse density to be 5% at b =0.025 fm and significantly better at large distances. New kaon data planned with the 12 GeV Jefferson Lab may have a significant impact on the charge density at distances of b <0.1 fm.

Asymptotic properties of the development of conformally flat data near spatial infinity

International Nuclear Information System (INIS)

Valiente Kroon, Juan Antonio

2007-01-01

The analysis of the relation between Bondi-type systems (NP-gauge) and a gauge used in the analysis of the structure of spatial infinity (F-gauge) which was carried out by Friedrich and Kannar (2000 J. Math Phys. 41 2195) is retaken and applied to the development of a suitable class of conformally flat initial data sets with non-vanishing second fundamental form. The calculations presented depend on a certain assumption about the existence and regularity of the solutions to the conformal Einstein field equations close to null and spatial infinity. As a result of the calculations the Newman-Penrose constants of both future and past null infinity are calculated in terms of initial data and are shown to be equal. It is also shown that the asymptotic shear goes to zero as one approaches spatial infinity along the generators of null infinity so that it is possible to select, in a canonical fashion, the Poincare group out of the BMS group. An expansion-again in terms of initial data quantities-of the Bondi mass close to spatial infinity is calculated. This expansion shows that if the existence and regularity assumptions hold, the Bondi mass approaches the ADM mass. A discussion of possible conditions on the initial data which would render a peeling development is presented

Application of E-infinity theory to biology

International Nuclear Information System (INIS)

He Jihuan

2006-01-01

Albert Einstein combined continuous space and time into his special relativity, El-Naschie discovered the transfinite discontinuity of space-time in his E-infinity theory where infinity of dimensions was created. We find a partner of both space-time and E-infinity in biology. In our theory, the number of cells in an organism endows an additional dimension in biology, leading to explanation of many complex phenomena

Plane waves and spacelike infinity

International Nuclear Information System (INIS)

Marolf, Donald; Ross, Simon F

2003-01-01

In an earlier paper, we showed that the causal boundary of any homogeneous plane wave satisfying the null convergence condition consists of a single null curve. In Einstein-Hilbert gravity, this would include any homogeneous plane wave satisfying the weak null energy condition. For conformally flat plane waves such as the Penrose limit of AdS 5 x S 5 , all spacelike curves that reach infinity also end on this boundary and the completion is Hausdorff. However, the more generic case (including, e.g., the Penrose limits of AdS 4 x S 7 and AdS 7 x S 4 ) is more complicated. In one natural topology, not all spacelike curves have limit points in the causal completion, indicating the need to introduce additional points at 'spacelike infinity' - the endpoints of spacelike curves. We classify the distinct ways in which spacelike curves can approach infinity, finding a two-dimensional set of distinct limits. The dimensionality of the set of points at spacelike infinity is not, however, fixed from this argument. In an alternative topology, the causal completion is already compact, but the completion is non-Hausdorff

Semiglobal H-infinity State Feedback Control

DEFF Research Database (Denmark)

Cromme, Marc; Stoustrup, Jakob

1996-01-01

Semi-global set-stabilizing H-infinity controlis a local within some given compact set such that all statetrajectories are bounded inside the set, and are approaching an openloop invariant subset as time approaches infinity. Sufficientconditions for the existence of a continuous state feedback law...

Conceptualisations of infinity by primary pre-service teachers

Science.gov (United States)

Date-Huxtable, Elizabeth; Cavanagh, Michael; Coady, Carmel; Easey, Michael

2018-05-01

As part of the Opening Real Science: Authentic Mathematics and Science Education for Australia project, an online mathematics learning module embedding conceptual thinking about infinity in science-based contexts, was designed and trialled with a cohort of 22 pre-service teachers during 1 week of intensive study. This research addressed the question: "How do pre-service teachers conceptualise infinity mathematically?" Participants argued the existence of infinity in a summative reflective task, using mathematical and empirical arguments that were coded according to five themes: definition, examples, application, philosophy and teaching; and 17 codes. Participants' reflections were differentiated as to whether infinity was referred to as an abstract (A) or a real (R) concept or whether both (B) codes were used. Principal component analysis of the reflections, using frequency of codings, revealed that A and R codes occurred at different frequencies in three groups of reflections. Distinct methods of argument were associated with each group of reflections: mathematical numerical examples and empirical measurement comparisons characterised arguments for infinity as an abstract concept, geometric and empirical dynamic examples and belief statements characterised arguments for infinity as a real concept and empirical measurement and mathematical examples and belief statements characterised arguments for infinity as both an abstract and a real concept. An implication of the results is that connections between mathematical and empirical applications of infinity may assist pre-service teachers to contrast finite with infinite models of the world.

On exclusive reactions in the time-like region

CERN Document Server

Kroll, P; Schürmann, M; Schweiger, W; Pilsner, Th.

1993-01-01

The electromagnetic form factors of the proton in the time-like region and two-photon annihilations into proton-antiproton are investigated. To calculate these processes at moderately large $s$ we use a variant of the Brodsky-Lepage hard-scattering formalism where diquarks are considered as quasi-elementary constituents of baryons. The proton wave function and the parameters controlling the diquark contributions are determined from fits to space-like data. We also comment on the decay $\\eta_c \\to p\\bar{p}$.

COSY INFINITY Version 9

International Nuclear Information System (INIS)

Makino, Kyoko; Berz, Martin

2006-01-01

In this paper, we review the features in the newly released version of COSY INFINITY, which currently has a base of more than 1000 registered users, focusing on the topics which are new and some topics which became available after the first release of the previous versions 8 and 8.1. The recent main enhancements of the code are devoted to reliability and efficiency of the computation, to verified integration, and to rigorous global optimization. There are various data types available in COSY INFINITY to support these goals, and the paper also reviews the feature and usage of those data types

Closed Timelike Curves in Type II Non-Vacuum Spacetime

International Nuclear Information System (INIS)

Ahmed, Faizuddin

2017-01-01

Here we present a cyclicly symmetric non-vacuum spacetime, admitting closed timelike curves (CTCs) which appear after a certain instant of time, i.e., a time-machine spacetime. The spacetime is asymptotically flat, free-from curvature singularities and a four-dimensional extension of the Misner space in curved spacetime. The spacetime is of type II in the Petrov classification scheme and the matter field pure radiation satisfy the energy condition. (paper)

Spacelike and timelike form factors for ω→πγ* and K*→Kγ* in the light-front quark model

International Nuclear Information System (INIS)

Choi, Ho-Meoyng

2008-01-01

We investigate space- and timelike form factors for ω→πγ* and K*→Kγ* decays using the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. The momentum dependent spacelike form factors are obtained in the q + =0 frame and then analytically continued to the timelike region. Our prediction for the timelike form factor F ωπ (q 2 ) is in good agreement with the experimental data. We also find that the spacelike form factor F K* ± K ± (Q 2 ) for charged kaons encounters a zero because of the negative interference between the two currents to the quark and the antiquark.

INFINITY construction contract signed

Science.gov (United States)

2010-01-01

Key state and community leaders celebrated April 6 with the signing of a construction contract for the state-of-the-art INFINITY Science Center planned near John C. Stennis Space Center in south Mississippi. Gulfport Mayor George Schloegel (l to r), chair of non-profit INFINITY Science Center Inc., was joined for the signing ceremony at the Hancock Bank in Gulfport by Virginia Wagner, sister of late Hancock Bank President Leo Seal Jr.; and Roy Anderson III, president and CEO of Roy Anderson Corp. Seal was the first chair of INFINITY Science Center Inc., which has led in development of the project. Roy Anderson Corp. plans to begin construction on the 72,000-square-foot, $28 million science and education center in May. The Mississippi Department of Transportation (MDOT) also is set to begin construction of a $2 million access road to the new center. The April 6 ceremony was attended by numerous officials, including former Stennis Space Center Directors Jerry Hlass and Roy Estess; Mississippi Senate President Pro Tempore Billy Hewes, R-Gulfport; Mississippi Rep. Diane Peranich, D-Pass Christian; and MDOT Southern District Commissioner Wayne Brown.

Local and global bifurcations at infinity in models of glycolytic oscillations

DEFF Research Database (Denmark)

Sturis, Jeppe; Brøns, Morten

1997-01-01

We investigate two models of glycolytic oscillations. Each model consists of two coupled nonlinear ordinary differential equations. Both models are found to have a saddle point at infinity and to exhibit a saddle-node bifurcation at infinity, giving rise to a second saddle and a stable node...... at infinity. Depending on model parameters, a stable limit cycle may blow up to infinite period and amplitude and disappear in the bifurcation, and after the bifurcation, the stable node at infinity then attracts all trajectories. Alternatively, the stable node at infinity may coexist with either a stable...... sink (not at infinity) or a stable limit cycle. This limit cycle may then disappear in a heteroclinic bifurcation at infinity in which the unstable manifold from one saddle at infinity joins the stable manifold of the other saddle at infinity. These results explain prior reports for one of the models...

The static gravitational field near spatial infinity

International Nuclear Information System (INIS)

Beig, R.

1980-01-01

A static solution to Einstein's equations, which is asymptotically flat near spatial infinity, is shown to be asymptotically Schwarzschildian. As an application of this result a technical lemma on the existence of asymptotically flat harmonic coordinates near infinity is proved. (author)

Conditions for the spectrum associated with an asymptotically straight leaky wire to comprise the interval (-{infinity}, {infinity})

Energy Technology Data Exchange (ETDEWEB)

Brown, B M; Eastham, M S P [Department of Computer Science, Cardiff University, Cardiff, CF24 3XF (United Kingdom); Wood, I G [Institute of Mathematics and Physics, Aberystwyth University, Penglais, Aberystwyth, Ceredigion, SY23 3BZ (United Kingdom)], E-mail: malcolm@cs.cf.ac.uk, E-mail: mandh@chesilhay.fsnet.co.uk, E-mail: iww@aber.ac.uk

2009-02-06

We consider a quantum (or leaky) wire in the plane, and the wire supports a singular attraction which becomes large at distant points on the wire. An analogous regular potential arises from the motion of a hydrogen atom in an electric field. We prove that, as in the regular case, the spectrum is the whole of (-{infinity}, {infinity})

Null infinity and extremal horizons in AdS-CFT

International Nuclear Information System (INIS)

Hickling, Andrew; Wiseman, Toby; Lucietti, James

2015-01-01

We consider AdS gravity duals to CFT on background spacetimes with a null infinity. Null infinity on the conformal boundary may extend to an extremal horizon in the bulk. For example it does so for Poincaré–AdS, although does not for planar Schwarzschild–AdS. If null infinity does extend into an extremal horizon in the bulk, we show that the bulk near-horizon geometry is determined by the geometry of the boundary null infinity. Hence the ‘infra-red’ geometry of the bulk is fixed by the large scale behaviour of the CFT spacetime. In addition the boundary stress tensor must have a particular decay at null infinity. As an application, we argue that for CFT on asymptotically flat backgrounds, any static bulk dual containing an extremal horizon extending from the boundary null infinity, must have the near-horizon geometry of Poincaré–AdS. We also discuss a class of boundary null infinity that cannot extend to a bulk extremal horizon, although we give evidence that they can extend to an analogous null surface in the bulk which possesses an associated scale-invariant ‘near-geometry’. (paper)

New infiniti Q45. Shingata Infiniti Q45'' ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Oka, T; Ochiai, A; Kato, Y [Nissan Motor Co. Ltd., Tokyo (Japan)

1989-12-25

This report introduces the concept for development and the outline of the Infiniti Q45, a new luxury sedan Nissan has developed, and special activities Nissan makes to produce luxury cars. This sedan was developed with the concept of producing a large-sized luxury car of evidently Japanese make to earn the world appraisal; a touring saloon whose style is original and unique based on the sensitivity of Japanese and yet which has the performance of a sports car. Every part of the Infiniti Q45, from the V8 engine and the 4.5 L DOHC 32 valve engine to the hydraulic active suspension, the first to be loaded on a mass production car, features Nissan's innovative and leading-edge technology. Moreover, to provide maximum customer satisfaction in every scene from the purchase of a car to services, various constructive programs have been adopted with the key word, Total Ownership Experience. 8 figs., 2 tabs.

The Omega-Infinity Limit of Single Spikes

CERN Document Server

Axenides, Minos; Linardopoulos, Georgios

A new infinite-size limit of strings in RxS2 is presented. The limit is obtained from single spike strings by letting their angular velocity omega become infinite. We derive the energy-momenta relation of omega-infinity single spikes as their linear velocity v-->1 and their angular momentum J-->1. Generally, the v-->1, J-->1 limit of single spikes is singular and has to be excluded from the spectrum and be studied separately. We discover that the dispersion relation of omega-infinity single spikes contains logarithms in the limit J-->1. This result is somewhat surprising, since the logarithmic behavior in the string spectra is typically associated with their motion in non-compact spaces such as AdS. Omega-infinity single spikes seem to completely cover the surface of the 2-sphere they occupy, so that they may essentially be viewed as some sort of "brany strings". A proof of the sphere-filling property of omega-infinity single spikes is given in the appendix.

Leaders break ground for INFINITY

Science.gov (United States)

2008-01-01

Community leaders from Mississippi and Louisiana break ground for the new INFINITY at NASA Stennis Space Center facility during a Nov. 20 ceremony. Groundbreaking participants included (l to r): Gottfried Construction representative John Smith, Mississippi Highway Commissioner Wayne Brown, INFINITY board member and Apollo 13 astronaut Fred Haise, Stennis Director Gene Goldman, Studio South representative David Hardy, Leo Seal Jr. family representative Virginia Wagner, Hancock Bank President George Schloegel, Mississippi Rep. J.P. Compretta, Mississippi Band of Choctaw Indians representative Charlie Benn and Louisiana Sen. A.G. Crowe.

Timelike symmetry of the quantum transition and Einstein-Podolsky-Rosen paradox

International Nuclear Information System (INIS)

Costa de Beauregard, Olivier

1976-01-01

The non-locality in the paradox is very close to that of Feynman's electron-positron system: the sum of two timelike vectors with 4th components of opposite signs may be spacelike. The intrinsic time symmetry of the quantum transition consists in the presence of both the delayed and the advanced wave inside the ''collapsed'' wave [fr

Dual Smarandache Curves of a Timelike Curve lying on Unit dual Lorentzian Sphere

OpenAIRE

Kahraman, Tanju; Hüseyin Ugurlu, Hasan

2016-01-01

In this paper, we give Darboux approximation for dual Smarandache curves of time like curve on unit dual Lorentzian sphere. Firstly, we define the four types of dual Smarandache curves of a timelike curve lying on dual Lorentzian sphere.

Isometries of half supersymmetric time-like solutions in five dimensions

International Nuclear Information System (INIS)

Gutowski, J B; Sabra, W A

2010-01-01

Spinorial geometry techniques have recently been used to classify all half supersymmetric solutions in gauged five-dimensional supergravity with vector multiplets. In this paper we consider solutions for which at least one of the Killing spinors generates a time-like Killing vector. We obtain coordinate transformations which considerably simplify the solutions, and in a number of cases, we obtain explicitly some additional Killing vectors which were hidden in the original analysis.

Timelike Compton scattering off the neutron and generalized parton distributions

Energy Technology Data Exchange (ETDEWEB)

Boer, M.; Guidal, M. [CNRS-IN2P3, Universite Paris-Sud, Institut de Physique Nucleaire d' Orsay, Orsay (France); Vanderhaeghen, M. [Johannes Gutenberg Universitaet, Institut fuer Kernphysik and PRISMA Cluster of Excellence, Mainz (Germany)

2016-02-15

We study the exclusive photoproduction of an electron-positron pair on a neutron target in the Jefferson Lab energy domain. The reaction consists of two processes: the Bethe-Heitler and the Timelike Compton Scattering. The latter process provides potentially access to the Generalized Parton Distributions (GPDs) of the nucleon. We calculate all the unpolarized, single- and double-spin observables of the reaction and study their sensitivities to GPDs. (orig.)

Noncrossing timelike singularities of irrotational dust collapse

International Nuclear Information System (INIS)

Liang, E.P.T.

1979-01-01

Known naked singularities in spherical dust collapse are either due to shell-crossing or localized to the central world line. They will probably be destroyed by pressure gradients or blue-shift instabilities. To violate the cosmic censorship hypothesis in a more convincing and general context, collapse solutions with naked singularities that are at least nonshell-crossing and nonlocalized need to be constructed. Some results concerning the probable structure of a class of nonshellcrossing and nonlocalized timelike singularities are reviewed. The cylindrical dust model is considered but this model is not asymptotically flat. To make these noncrossing singularities viable counter examples to the cosmic censorship hypothesis, the occurrence of such singularities in asymptotically flat collapse needs to be demonstrated. (UK)

Takagi-Sugeno Fuzzy Systems Non-fragile H-infinity Filtering

CERN Document Server

Chang, Xiao-Heng

2012-01-01

"Takagi-Sugeno Fuzzy Systems Non-fragile H-infinity Filtering" investigates the problem of non-fragile H-infinity filter design for T-S fuzzy systems. The nonlinear plant is represented by a T-S fuzzy model. Given a T-S fuzzy system, the objective of this book is to design an H-infinity filter with the gain variations such that the filtering error system guarantees a prescribed H-infinity performance level. Furthermore, it demonstrates that the solution of non-fragile H-infinity filter design problem can be obtained by solving a set of linear matrix inequalities (LMIs). The intended audiences are graduate students and researchers both from the fields of engineering and mathematics. Dr. Xiao-Heng Chang is an Associate Professor at the College of Engineering, Bohai University, Jinzhou, Liaoning, China. He is also a Postdoctoral Researcher at the College of Information Science and Engineering, Northeastern University, Shenyang, China.

NNLO splitting and coefficient functions with time-like kinematics

International Nuclear Information System (INIS)

Mitov, A.; Moch, S.; Vogt, A.; Liverpool Univ.

2006-09-01

We discuss recent results on the three-loop (next-to-next-to-leading order, NNLO) time-like splitting functions of QCD and the two-loop (NNLO) coefficient functions in one-particle inclusive e + e - -annihilation. These results form the basis for extracting fragmentation functions for light and heavy flavors with NNLO accuracy that will be needed at the LHC and ILC. The two-loop calculations have been performed in Mellin space bases on a new method, the main features of which we also describe briefly. (orig.)

The Universe, Time, Eternity and Infinity

Directory of Open Access Journals (Sweden)

Lolaev T. P.

2013-04-01

Full Text Available The conceptions of «universe», «eternity», «time» and «infinity» belong to the list of the most fundamental and complex characteristics of the matter. The concepts of "universe", "eternity", "time" and "infinity" is defined in article in fundamentally new interpretation. This was made possible thanks to the identification by the author the nature of time, and formulation and theoretically and experimentally justification of the Law of the Universe functioning.

Notes on the infinity Laplace equation

CERN Document Server

Lindqvist, Peter

2016-01-01

This BCAM SpringerBriefs is a treaty of the Infinity-Laplace Equation, which has inherited many features from the ordinary Laplace Equation, and is based on lectures by the author. The Infinity.Laplace Equation has delightful counterparts to the Dirichlet integral, the mean value property, the Brownian motion, Harnack's inequality, and so on. This "fully non-linear" equation has applications to image processing and to mass transfer problems, and it provides optimal Lipschitz extensions of boundary values.

Translating The Infinities by John Banville

OpenAIRE

Irene Abigail Piccinini

2015-01-01

Abstract - John Banville’s talent as a prose stylist is widely recognized. The polished elegance of his phrases constitutes a continuing and fascinating challenge for his translator, due to the intricacies of the source text, its manifold registers and lexical choices. In his novel The Infinities, in Italian Teoria degli Infiniti, John Banville takes cue from Kleist’s Amphytrion to devise a novel where classicality interweaves with science and science fiction through the invention of a world ...

Spatial infinity in higher dimensional spacetimes

International Nuclear Information System (INIS)

Shiromizu, Tetsuya; Tomizawa, Shinya

2004-01-01

Motivated by recent studies on the uniqueness or nonuniqueness of higher dimensional black hole spacetime, we investigate the asymptotic structure of spatial infinity in n-dimensional spacetimes (n≥4). It turns out that the geometry of spatial infinity does not have maximal symmetry due to the nontrivial Weyl tensor (n-1) C abcd in general. We also address static spacetime and its multipole moments P a 1 a 2 ···a s . Contrasting with four dimensions, we stress that the local structure of spacetimes cannot be unique under fixed multipole moments in static vacuum spacetimes. For example, we consider the generalized Schwarzschild spacetimes which are deformed black hole spacetimes with the same multipole moments as spherical Schwarzschild black holes. To specify the local structure of the static vacuum solution we need some additional information, at least the Weyl tensor (n-2) C abcd at spatial infinity

K/sub infinity/-meter concept verified via subcritical-critical TRIGA experiments

International Nuclear Information System (INIS)

Ocampo Mansilla, H.

1983-01-01

This work presents a technique for building a device to measure the k/sub infinity/ of a spent nuclear fuel assembly discharged from the core of a nuclear power plant. The device, called a k/sub infinity/-meter, consists of a cross-shaped subcritical assembly, two artificial neutron sources, and two separate neutron counting systems. The central position of the subcritical assembly is used to measure k/sub infinity/ of the spent fuel assembly. The initial subcritical assembly is calibrated to determine its k/sub eff/ and verify the assigned k/sub infinity/ of a selected fuel assembly placed in the central position. Count rates are taken with the fuel assembly of known k/sub infinity/'s placed in the central position and then repeated with a fuel assembly of unknown k/sub infinity/ placed in the central position. The count rate ratio of the unknown fuel assembly to the known fuel assembly is used to determine the k/sub infinity/ of the unknown fuel assembly. The k/sub infinity/ of the unknown fuel assembly is represented as a polynomial function of the count rate ratios. The coefficients of the polynomial equation are determined using the neutronic codes LEOPARD and EXTERMINATOR-II. The analytical approach has been validated by performing several subcritical/critical experiments, using the Penn State Breazeale TRIGA Reactor (PSBR), and comparing the experimental results with the calculations

Homotopy Algorithm for Fixed Order Mixed H2/H(infinity) Design

Science.gov (United States)

Whorton, Mark; Buschek, Harald; Calise, Anthony J.

1996-01-01

Recent developments in the field of robust multivariable control have merged the theories of H-infinity and H-2 control. This mixed H-2/H-infinity compensator formulation allows design for nominal performance by H-2 norm minimization while guaranteeing robust stability to unstructured uncertainties by constraining the H-infinity norm. A key difficulty associated with mixed H-2/H-infinity compensation is compensator synthesis. A homotopy algorithm is presented for synthesis of fixed order mixed H-2/H-infinity compensators. Numerical results are presented for a four disk flexible structure to evaluate the efficiency of the algorithm.

COSY INFINITY, a new arbitrary order optics code

International Nuclear Information System (INIS)

Berz, M.

1990-01-01

The new arbitrary order particle optics and beam dynamics code COSY INFINITY is presented. The code is based on differential algebraic (DA) methods. COSY INFINITY has a full structured object oriented language environment. This provides a simple interface for the casual or novice user. At the same time, it offers the advanced user a very flexible and powerful tool for the utilization of DA. The power and generality of the environment is perhaps best demonstrated by the fact that the physics routines of COSY INFINITY are written in its own input language. The approach also facilitates the implementation of new features because special code generated by a user can be readily adopted to the source code. Besides being very compact in size, the code is also very fast, thanks to efficiently programmed elementary DA operations. For simple low order problems, which can be handled by conventional codes, the speed of COSY INFINITY is comparable and in certain cases even higher

New infiniti Q45. Shingata Infiniti Q45'' ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Oka, T.; Ochiai, A.; Kato, Y. (Nissan Motor Co. Ltd., Tokyo (Japan))

1989-12-25

This report introduces the concept for development and the outline of the Infiniti Q45, a new luxury sedan Nissan has developed, and special activities Nissan makes to produce luxury cars. This sedan was developed with the concept of producing a large-sized luxury car of evidently Japanese make to earn the world appraisal; a touring saloon whose style is original and unique based on the sensitivity of Japanese and yet which has the performance of a sports car. Every part of the Infiniti Q45, from the V8 engine and the 4.5 L DOHC 32 valve engine to the hydraulic active suspension, the first to be loaded on a mass production car, features Nissan's innovative and leading-edge technology. Moreover, to provide maximum customer satisfaction in every scene from the purchase of a car to services, various constructive programs have been adopted with the key word, Total Ownership Experience. 8 figs., 2 tabs.

The super-W sub infinity (. lambda. ) algebra

Energy Technology Data Exchange (ETDEWEB)

Bergshoeff, E; Vasiliev, M [European Organization for Nuclear Research, Geneva (Switzerland). Theory Div.; Wit, B de [Rijksuniversiteit Utrecht (Netherlands). Inst. voor Theoretische Fysica

1991-03-07

We present the super-W{sub {infinity}}({lambda}) algebra, an extension of the Virasoro algebra that contains operators of al spins s {ge} 1/2 and depends on an arbitrary parameter {lambda}. It encompasses all previously known versions of W{sub {infinity}}-type algebras as special cases. We discuss various properties and truncations of the algebra and present a realization in terms of the currents of a supersymmetric bc system. (orig.).

Comparison of two Ssub(infinity) methods for solving the neutron transport equation

International Nuclear Information System (INIS)

Mennig, J.; Brandt, D.; Haelg, W.

1978-01-01

A semianalytic method (S 0 sub(infinity)) is presented for solving the monoenergetic multi-region transport equation. This method is compared with results from S 1 sub(infinity)-theory given in the literature. Application of S 1 sub(infinity)-theory to reactor shields may lead to negative neutron fluxes and to flux oscillations. These unphysical effects are completely avoided by the new method. Numerical results demonstrate the limitations of S 1 sub(infinity) and confirm the numerical stability of (S 0 sub(infinity)). (Auth.)

Timelike Completeness as an Obstruction to C 0-Extensions

Science.gov (United States)

Galloway, Gregory J.; Ling, Eric; Sbierski, Jan

2017-11-01

The study of low regularity (in-)extendibility of Lorentzian manifolds is motivated by the question whether a given solution to the Einstein equations can be extended (or is maximal) as a weak solution. In this paper we show that a timelike complete and globally hyperbolic Lorentzian manifold is C 0-inextendible. For the proof we make use of the result, recently established by Sämann (Ann Henri Poincaré 17(6):1429-1455, 2016), that even for continuous Lorentzian manifolds that are globally hyperbolic, there exists a length-maximizing causal curve between any two causally related points.

On the infinities of closed superstring amplitudes

International Nuclear Information System (INIS)

Restuccia, A.; Taylor, J.G.

1988-01-01

The authors present an analysis of possible infinities that may be present in uncompactified multi-loop heterotic and type II superstring amplitudes constructed, without use of the short-string limit, in the light-cone gauge, and with use of a closed [10]-SUSY field theory algebra. Various types of degenerations of the integrand are discussed on the string worldsheet. No infinities are found, modulo (for type II) a particular identity for Green's functions

Three-dimensional nonlinear H-infinity guidance design and H-infinity-based pursuit-evasion game

Science.gov (United States)

Chen, Hsin-Yuan; Yang, Chi-Ching

2001-08-01

There are five features in this approach: (1) The complete nonlinear dynamics of the pursuit-evasion motion is considered in 3D spherical coordinate system. Neither linearization nor small signal assumptions are made. (2) The nonlinear H-infinity guidance design is derived analytically and expressed in a very simple form. (3) Unlike adaptive control concept, implementation of the proposed H(infinity ) guidance design does not need the information on target acceleration while ensuring acceptable intercept performance for arbitrary targets with the finite acceleration. (4) The derived guidance design exhibits strong robustness against variations in target acceleration. (5) Finally the issues related to the validation of the control law using Hardware In The Loop simulation are presented. The effects of the Flight Motion Simulator static and dynamic accuracies (time delay etc...) are discussed.

Bosonization of non-relativistic fermions and W-infinity algebra

International Nuclear Information System (INIS)

Das, S.R.; Dhar, A.; Mandal, G.; Wadia, S.R.

1992-01-01

In this paper the authors discuss the bosonization of non-relativistic fermions in one-space dimension in terms of bilocal operators which are naturally related to the generators of W-infinity algebra. The resulting system is analogous to the problem of a spin in a magnetic field for the group W-infinity. The new dynamical variables turn out to be W-infinity group elements valued in the coset W-infinity/H where H is a Cartan subalgebra. A classical action with an H gauge invariance is presented. This action is three-dimensional. It turns out to be similar to the action that describes the color degrees of freedom of a Yang-Mills particle in a fixed external field. The authors also discuss the relation of this action with the one recently arrived at in the Euclidean continuation of the theory using different coordinates

Wave equation in curved spacetime

Energy Technology Data Exchange (ETDEWEB)

Choquet-Bruhat, Y [Paris-6 Univ., 75 (France). Dept. de Mecanique; Christodoulou, D [Max-Planck-Institut fuer Physik und Astrophysik, Muenchen (Germany, F.R.); Francaviglia, M [Istituto di Fisica Matematica, Turin (Italy)

1979-01-01

We study the case where g tends at timelike infinity to a stationary metric, we prove some existence theorems in spaces of solutions with finite energy for all times, and also with finite s-order energy.

The Mathematics of Infinity A Guide to Great Ideas

CERN Document Server

Faticoni, Theodore G

2012-01-01

Praise for the First Edition ". . . an enchanting book for those people in computer science or mathematics who are fascinated by the concept of infinity."—Computing Reviews ". . . a very well written introduction to set theory . . . easy to read and well suited for self-study . . . highly recommended."—Choice The concept of infinity has fascinated and confused mankind for centuries with theories and ideas that cause even seasoned mathematicians to wonder. The Mathematics of Infinity: A Guide to Great Ideas, Second Edition uniquely explores how we can manipulate these ideas when

On timelike supersymmetric solutions of gauged minimal 5-dimensional supergravity

Energy Technology Data Exchange (ETDEWEB)

Chimento, Samuele; Ortín, Tomás [Instituto de Física Teórica UAM/CSIC,C/Nicolás Cabrera, 13-15, C.University Cantoblanco, E-28049 Madrid (Spain)

2017-04-04

We analyze the timelike supersymmetric solutions of minimal gauged 5-dimensional supergravity for the case in which the Kähler base manifold admits a holomorphic isometry and depends on two real functions satisfying a simple second-order differential equation. Using this general form of the base space, the equations satisfied by the building blocks of the solutions become of, at most, fourth degree and can be solved by simple polynomic ansatzs. In this way we construct two 3-parameter families of solutions that contain almost all the timelike supersymmetric solutions of this theory with one angular momentum known so far and a few more: the (singular) supersymmetric Reissner-Nordström-AdS solutions, the three exact supersymmetric solutions describing the three near-horizon geometries found by Gutowski and Reall, three 1-parameter asymptotically-AdS{sub 5} black-hole solutions with those three near-horizon geometries (Gutowski and Reall’s black hole being one of them), three generalizations of the Gödel universe and a few potentially homogenous solutions. A key rôle in finding these solutions is played by our ability to write AdS{sub 5}’s Kähler base space ( (ℂℙ)-bar {sup 2} or SU(1,2)/U(2)) is three different, yet simple, forms associated to three different isometries. Furthermore, our ansatz for the Kähler metric also allows us to study the dimensional compactification of the theory and its solutions in a systematic way.

On the Lojasiewicz exponent at infinity of real polynomials

International Nuclear Information System (INIS)

Ha Huy Vui; Pham Tien Son

2007-07-01

Let f : R n → R be a nonconstant polynomial function. In this paper, using the information from 'the curve of tangency' of f, we provide a method to determine the Lojasiewicz exponent at infinity of f. As a corollary, we give a computational criterion to decide if the Lojasiewicz exponent at infinity is finite or not. Then, we obtain a formula to calculate the set of points at which the polynomial f is not proper. Moreover, a relation between the Lojasiewicz exponent at infinity of f with the problem of computing the global optimum of f is also established. (author)

Translating The Infinities by John Banville

Directory of Open Access Journals (Sweden)

Irene Abigail Piccinini

2015-12-01

Full Text Available Abstract - John Banville’s talent as a prose stylist is widely recognized. The polished elegance of his phrases constitutes a continuing and fascinating challenge for his translator, due to the intricacies of the source text, its manifold registers and lexical choices. In his novel The Infinities, in Italian Teoria degli Infiniti, John Banville takes cue from Kleist’s Amphytrion to devise a novel where classicality interweaves with science and science fiction through the invention of a world where the ancient gods intermingle with the humans while waiting for the death of Adam Godley, a famous mathematician who explained how an infinity of worlds exist and interact with each other. To translate this book I had not only to work extensively on lexis and style, but also to do considerable research to render the many literary and non literary references. Some examples of these struggles with the source text during the translation process are given in the present paper. Riassunto - John Banville, autore irlandese noto per la sua prosa raffinata, scrive in una lingua che rappresenta una sfida continua e affascinante per chi lo traduce. La sua complessità stilistica, che sfrutta molteplici registri linguistici e si avvale di scelte lessicali cui spesso è arduo trovare un traducente italiano soddisfacente, costringe il traduttore a fare ricorso a tutte le sottigliezze del proprio mestiere per restituire quanto più possibile l’eleganza dell’originale nella propria lingua. Nel romanzo The Infinities, tradotto in italiano come Teoria degli infiniti (Guanda, Parma 2011, Banville prende spunto dall’Anfitrione di Kleist per costruire un romanzo che guarda alla classicità sconfinando in un misto di scienza e fantascienza con la concezione di un’infinità di mondi paralleli teorizzata dal matematico Adam Godley, il protagonista morente al cui capezzale si radunano uomini e antichi dei in attesa che il cerchio della vita e della morte si compia

Exact string theory model of closed timelike curves and cosmological singularities

International Nuclear Information System (INIS)

Johnson, Clifford V.; Svendsen, Harald G.

2004-01-01

We study an exact model of string theory propagating in a space-time containing regions with closed timelike curves (CTCs) separated from a finite cosmological region bounded by a big bang and a big crunch. The model is an nontrivial embedding of the Taub-NUT geometry into heterotic string theory with a full conformal field theory (CFT) definition, discovered over a decade ago as a heterotic coset model. Having a CFT definition makes this an excellent laboratory for the study of the stringy fate of CTCs, the Taub cosmology, and the Milne/Misner-type chronology horizon which separates them. In an effort to uncover the role of stringy corrections to such geometries, we calculate the complete set of α ' corrections to the geometry. We observe that the key features of Taub-NUT persist in the exact theory, together with the emergence of a region of space with Euclidean signature bounded by timelike curvature singularities. Although such remarks are premature, their persistence in the exact geometry is suggestive that string theory is able to make physical sense of the Milne/Misner singularities and the CTCs, despite their pathological character in general relativity. This may also support the possibility that CTCs may be viable in some physical situations, and may be a natural ingredient in pre-big bang cosmological scenarios

On the geometry of null cones to infinity under curvature flux bounds

International Nuclear Information System (INIS)

Alexakis, Spyros; Shao, Arick

2014-01-01

The main objective of this paper is to control the geometry of a future outgoing truncated null cone extending smoothly toward infinity in an Einstein-vacuum spacetime. In particular, we wish to do this under minimal regularity assumptions, namely, at the (weighted) L 2 -curvature level. We show that if the curvature flux and the data on an initial sphere of the cone are sufficiently close to the corresponding values in a standard Minkowski or Schwarzschild null cone, then we can obtain quantitative bounds on the geometry of the entire infinite cone. The same bounds also imply the existence of limits at infinity, along the null cone, of naturally scaled geometric quantities. In Alexakis and Shao (2013 Bounds on the Bondi energy by a flux of curvature arXiv:1308.4170), we will apply these results in order to control various physical quantities—e.g., the Bondi energy and (linear and angular) momenta—associated with such infinite null cones in vacuum spacetimes. (paper)

Surprising structures hiding in Penrose’s future null infinity

Science.gov (United States)

Newman, Ezra T.

2017-07-01

Since the late1950s, almost all discussions of asymptotically flat (Einstein-Maxwell) space-times have taken place in the context of Penrose’s null infinity, I+. In addition, almost all calculations have used the Bondi coordinate and tetrad systems. Beginning with a known asymptotically flat solution to the Einstein-Maxwell equations, we show first, that there are other natural coordinate systems, near I+, (analogous to light-cones in flat-space) that are based on (asymptotically) shear-free null geodesic congruences (analogous to the flat-space case). Using these new coordinates and their associated tetrad, we define the complex dipole moment, (the mass dipole plus i times angular momentum), from the l  =  1 harmonic coefficient of a component of the asymptotic Weyl tensor. Second, from this definition, from the Bianchi identities and from the Bondi-Sachs mass and linear momentum, we show that there exists a large number of results—identifications and dynamics—identical to those of classical mechanics and electrodynamics. They include, among many others, {P}=M{v}+..., {L}= {r} × {P} , spin, Newton’s second law with the rocket force term (\\dotM v) and radiation reaction, angular momentum conservation and others. All these relations take place in the rather mysterious H-space rather than in space-time. This leads to the enigma: ‘why do these well known relations of classical mechanics take place in H-space?’ and ‘What is the physical meaning of H-space?’

Time asymmetric spacetimes near null and spatial infinity: II. Expansions of developments of initial data sets with non-smooth conformal metrics

International Nuclear Information System (INIS)

Kroon, Juan Antonio Valiente

2005-01-01

This paper uses the conformal Einstein equations and the conformal representation of spatial infinity introduced by Friedrich to analyse the behaviour of the gravitational field near null and spatial infinity for the development of initial data which are, in principle, non-conformally flat and time asymmetric. The paper is the continuation of the investigation started in Class. Quantum Grav. 21 (2004) 5457-92, where only conformally flat initial data sets were considered. For the purposes of this investigation, the conformal metric of the initial hypersurface is assumed to have a very particular type of non-smoothness at infinity in order to allow for the presence of non-Schwarzschildean stationary initial data sets in the class under study. The calculation of asymptotic expansions of the development of these initial data sets reveals-as in the conformally flat case-the existence of a hierarchy of obstructions to the smoothness of null infinity which are expressible in terms of the initial data. This allows for the possibility of having spacetimes where future and past null infinity have different degrees of smoothness. A conjecture regarding the general structure of the hierarchy of obstructions is presented

On the L-Infinity Description of the Hitchin Map

International Nuclear Information System (INIS)

Dalakov, Peter

2010-07-01

Recently, E. Martinengo obtained results on obstructions to deformations of Higgs pairs by describing an L-infinity morphism inducing the Hitchin map. In this note we show that analogous results hold for principal G-Higgs bundles. Moreover, we show that the L-infinity morphism is a 'global analogue' of a Lie-algebraic construction. (author)

The structure of the super-W sub infinity (. lambda. ) algebra

Energy Technology Data Exchange (ETDEWEB)

Bergshoeff, E [CERN, Geneva (Switzerland). Theory Div.; Wit, B de [Utrecht Univ. (Netherlands). Inst. for Theoretical Physics; Vasiliev, M [AN SSSR, Moscow (USSR). Theoretical Dept., P.N. Lebedev Inst.

1991-12-02

We give a comprehensive treatment of the super-W{sub {infinity}}({lambda}) algebra, an extension of the super-Virasoro algebra that contains generators of spin S {>=} 1/2. The parameter {lambda} defines the embedding of the Virasoro subalgebra. We describe how to obtain the super-W{sub {infinity}}({lambda}) algebra from the associative algebra of superspace differential operators. We discuss the structure of this associative algebra and its relation with the so-called wedge algebra, in which the generators for given spin are restricted to finite-dimensional representations of sl(2). From the super-W{sub {infinity}}({lambda}) algebra one can obtain a variety of W{sub {infinity}} algebras by consistent truncations for specific values of {lambda}. Without truncation the algebras are formally isomorphic for different values of {lambda}. We present a realization in terms of the currents of a supersymmetric bc system. (orig.).

Dilemma Produced by Infinity of a Random Walk

International Nuclear Information System (INIS)

Li Jing-Hui

2015-01-01

We report a dilemma produced by the infinity of a random walk moving along a two-dimensional space sidestep. For this random walk, our investigation shows that using a different model can lead to a different diffusion coefficient of the random walk, which is produced by the infinity of the random walk. The result obtained by us in the present work can serve as a warning to us when we build the models to investigate the corresponding scientific problems. (paper)

Thermal imaging comparison of Signature, Infiniti, and Stellaris phacoemulsification systems.

Science.gov (United States)

Ryoo, Na Kyung; Kwon, Ji-Won; Wee, Won Ryang; Miller, Kevin M; Han, Young Keun

2013-10-12

To compare the heat production of 3 different phacoemulsification machines under strict laboratory test conditions. More specifically, the thermal behavior was analyzed between the torsional modality of the Infiniti system and longitudinal modalities of the Abbot WhiteStar Signature Phacoemulsification system and Bausch and Lomb Stellaris system. Experiments were performed under in-vitro conditions in this study.Three phacoemulsification handpieces (Infiniti, Signature, and Stellaris) were inserted into balanced salt solution-filled silicone test chambers and were imaged side-by-side by using a thermal camera. Incision compression was simulated by suspending 30.66-gram weights from the silicone chambers. The irrigation flow rate was set at 0, 1, 2, 3, 4, and 5 cc/min and the phacoemulsification power on the instrument consoles was set at 40, 60, 80, and 100%. The highest temperatures generated from each handpiece around the point of compression were measured at 0, 10, 30, and 60 seconds. Under the same displayed phacoemulsification power settings, the peak temperatures measured when using the Infiniti were lower than when using the other two machines, and the Signature was cooler than the Stellaris. At 10 seconds, torsional phacoemulsification with Infiniti at 100% power showed data comparable to that of the Signature at 80% and the Stellaris at 60%. At 30 seconds, the temperature from the Infiniti at 100% power was lower than the Signature at 60% and the Stellaris at 40%. Torsional phacoemulsification with the Infiniti generates less heat than longitudinal phacoemulsification with the Signature and the Stellaris. Lower operating temperatures indicate lower heat generation within the same fluid volume, which may provide additional thermal protection during cataract surgery.

Topics in the mathematical physics of E-infinity theory

International Nuclear Information System (INIS)

El Naschie, M.S.

2006-01-01

This is the fourth contribution in a series of papers aimed at directing the attention of the prospective E-infinity researcher to the most important mathematical background and sources needed for an easy understanding and successful application of this theory. The present paper is mainly concerned with the mathematical physics relevant to E-infinity theory with emphasis on super Yang-Mills theory and superstrings

A Review of "Infinity Factory."

Science.gov (United States)

National Council of Teachers of Mathematics, Inc., Reston, VA.

Following a discussion of the historical background of the TV series "Infinity Factory," the goals of the television project are listed. A general description of the television series, an evaluation of the entertainment value, and an evaluation of children's attitude change are briefly presented. The program's presentation of mathematics…

FLAT TIME-LIKE SUBMANIFOLDS IN ANTI-DE SITTER SPACE H12n-1(-1)

Institute of Scientific and Technical Information of China (English)

ZUO DAFENG; CHEN QING; CHENG YI

2005-01-01

By using dressing actions of the Gn-1 1,1,n-1-system, the authors study geometric transformations for flat time-like n-submanifolds with flat, non-degenerate normal bun dle in anti-de Sitter space H1 2n-1(-1), where G1,1 n-1,n-1= O(2n - 2, 2)/O(n - 1, 1) ×O(n - 1, 1).

COSY INFINITY version 8

International Nuclear Information System (INIS)

Makino, Kyoko; Berz, Martin

1999-01-01

The latest version of the particle optics code COSY INFINITY is presented. Using Differential Algebraic (DA) methods, the code allows the computation of aberrations of arbitrary field arrangements to in principle unlimited order. Besides providing a general overview of the code, several recent techniques developed for specific applications are highlighted. These include new features for the direct utilization of detailed measured fields as well as rigorous treatment of remainder bounds

Bolzano's Approach to the Paradoxes of Infinity: Implications for Teaching

Science.gov (United States)

Waldegg, Guillermina

2005-01-01

In this paper we analyze excerpts of "Paradoxes of the Infinite", the posthumous work of Bernard Bolzano (1781-1848), in order to show that Georg Cantor's (1845-1918) approach to the problem of defining actual mathematical infinity is not the most natural. In fact, Bolzano's approach to the paradoxes of infinity is more intuitive, while remaining…

Chiral chains for lattice quantum chromodynamics at N/sub c/=infinity

International Nuclear Information System (INIS)

Brower, R.C.; Rossi, P.; Tan, C.

1981-01-01

We study chiral fields [U/sub i/ in the group U(N)] on a periodic lattice (U/sub i/=U/sub i/+L), with action S1/=(g-italic 2 )Σ/sup L//sub l/=1Tr(U/sub l/U/sup //sub l/+1+ U/sup //sub l/U/sub l/+1), as prototypes for lattice gauge theories [quantum chromodynamics (QCD)] at N/sub c/=infinity. Indeed, these chiral chains are equivalent to gauge theories on the surface of an L-faced polyhedron (e.g., L=4 is a tetrahedron, L=6 is the cube, and L=infinity is two-dimensional QCD). The one-link Schwinger-Dyson equation of Brower and Nauenberg, which gives the square of the transfer matrix, is solved exactly for all N. From the large-N solution, we solve exactly the finite chains for L=2, 3, 4, and infinity, on the weak-coupling side of the Gross-Witten singularity, which occurs at β=(g-italic 2 N) -1 =1/4, 1/3, π/8, and 1/2, respectively. We carry out weak and strong perturbation expansions at N/sub c/=infinity to estimate the singular part for all L, and to show confinement (as g 2 N→infinity) and asymptotic freedom (g 2 N→0) in the Migdal β function for QCD. The stability of the location of the Gross-Witten singularity for different-size lattices (L) suggests that QCD at N/sub c/=infinity enjoys this singularity in the transition region from strong to weak coupling

Comparison of the Infiniti vision and the series 20,000 Legacy systems.

Science.gov (United States)

Fernández de Castro, Luis E; Solomon, Kerry D; Hu, Daniel J; Vroman, David T; Sandoval, Helga P

2008-01-01

To compare the efficiency of the Infiniti vision system and the Series 20,000 Legacy system phacoemulsification units during routine cataract extraction. Thirty-nine eyes of 39 patients were randomized to have their cataract removed using either the Infiniti or the Legacy system, both using the Neosonix handpiece. System settings were standardized. Ultrasound time, amount of balanced salt solution (BSS) used intraoperatively, and postoperative visual acuity at postoperative days 1, 7 and 30 were evaluated. Preoperatively, best corrected visual acuity was significantly worse in the Infiniti group compared to the Legacy group (0.38 +/- 0.23 and 0.21 +/- 0.16, respectively; p = 0.012). The mean phacoemulsification time was 39.6 +/- 22.9 s (range 6.0-102.0) for the Legacy group and 18.3 +/-19.1 s (range 1.0-80.0) for the Infiniti group (p = 0.001). The mean amounts of intraoperative BSS used were 117 +/- 37.7 ml (range 70-195) in the Legacy group and 85.3 +/- 38.9 ml (range 40-200) in the Infiniti group (p = 0.005). No differences in postoperative visual acuity were found. The ability to use higher flow rates and vacuum settings with the Infiniti vision system allowed for cataract removal with less phacoemulsification time than when using the Legacy system. Copyright 2008 S. Karger AG, Basel.

Asymptotically AdS spacetimes with a timelike Kasner singularity

Energy Technology Data Exchange (ETDEWEB)

Ren, Jie [Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel)

2016-07-21

Exact solutions to Einstein’s equations for holographic models are presented and studied. The IR geometry has a timelike cousin of the Kasner singularity, which is the less generic case of the BKL (Belinski-Khalatnikov-Lifshitz) singularity, and the UV is asymptotically AdS. This solution describes a holographic RG flow between them. The solution’s appearance is an interpolation between the planar AdS black hole and the AdS soliton. The causality constraint is always satisfied. The entanglement entropy and Wilson loops are discussed. The boundary condition for the current-current correlation function and the Laplacian in the IR is examined. There is no infalling wave in the IR, but instead, there is a normalizable solution in the IR. In a special case, a hyperscaling-violating geometry is obtained after a dimensional reduction.

Infinity and the mind the science and philosophy of the infinite

CERN Document Server

Rucker, Rudy

2005-01-01

In Infinity and the Mind, Rudy Rucker leads an excursion to that stretch of the universe he calls the "Mindscape," where he explores infinity in all its forms: potential and actual, mathematical and physical, theological and mundane. Rucker acquaints us with Gödel's rotating universe, in which it is theoretically possible to travel into the past, and explains an interpretation of quantum mechanics in which billions of parallel worlds are produced every microsecond. It is in the realm of infinity, he maintains, that mathematics, science, and logic merge with the fantastic. By closely examining the paradoxes that arise from this merging, we can learn a great deal about the human mind, its powers, and its limitations. Using cartoons, puzzles, and quotations to enliven his text, Rucker guides us through such topics as the paradoxes of set theory, the possibilities of physical infinities, and the results of Gödel's incompleteness theorems. His personal encounters with Gödel the mathematician and philosopher pr...

The infinity puzzle

CERN Document Server

Close, Frank

2011-01-01

We are living in a Golden Age of Physics. Forty or so years ago, three brilliant, yet little-known scientists - an American, a Dutchman, and an Englishman - made breakthroughs which later inspired the construction of the Large Hadron Collider at CERN in Geneva: a 27 kilometer-long machine which has already costs ten billion dollars, taken twenty years to build, and now promises to reveal how the universe itself came to be. The Infinity Puzzle is the inside story of those forty years of research, breakthrough, and endeavour. Peter Higgs, Gerard 't Hooft and James Bjorken, were the three scienti

Limiting procedure T→ infinity in the Hill method for quasi-energetic states

International Nuclear Information System (INIS)

Melikyan, A.O.; Simonyan, K.Kh.

1980-01-01

A connection between the quasi-energetic states of a quantum system in a time-periodic field when the period tends to infinity and the nonstationary states in a nonperiodic field vanishing at t→infinity is established

Bolzano`s Approach to the Paradoxes of Infinity: Implications for Teaching

Science.gov (United States)

Waldegg, Guillermina

2005-08-01

In this paper we analyze excerpts of Paradoxes of the Infinite, the posthumous work of Bernard Bolzano (1781-1848), in order to show that Georg Cantor‘s (1845-1918) approach to the problem of defining actual mathematical infinity is not the most natural. In fact, Bolzano‘s approach to the paradoxes of infinity is more intuitive, while remaining internally coherent. Bolzano‘s approach, however, had limitations. We discuss implications for teaching, which include a better understanding of the responses of students to situations involving actual mathematical infinity, for it is possible to draw a kind of parallel between these responses and Bolzano‘s reasoning.

Infinity and the mind the science and philosophy of the infinite

CERN Document Server

Rucker, Rudy

1984-01-01

Infinity and the mind is a fascinating introduction to different number systems, to set theory, to logical paradoxes, to the ideas behind artificial intelligence. It includes detailed discussions of George Cantor's transfinite cardinal numbers and Kurt Gödel's Incompleteness Theorems. And it also relates our ideas of infinity to the great mystic traditions.

L{sup {infinity}} Variational Problems with Running Costs and Constraints

Energy Technology Data Exchange (ETDEWEB)

Aronsson, G., E-mail: gunnar.aronsson@liu.se [Linkoeping University, Department of Mathematics (Sweden); Barron, E. N., E-mail: enbarron@math.luc.edu [Loyola University of Chicago, Department of Mathematics and Statistics (United States)

2012-02-15

Various approaches are used to derive the Aronsson-Euler equations for L{sup {infinity}} calculus of variations problems with constraints. The problems considered involve holonomic, nonholonomic, isoperimetric, and isosupremic constraints on the minimizer. In addition, we derive the Aronsson-Euler equation for the basic L{sup {infinity}} problem with a running cost and then consider properties of an absolute minimizer. Many open problems are introduced for further study.

Hierarchy of wool fibers and its interpretation using E-infinity theory

International Nuclear Information System (INIS)

He Jihuan; Ren Zhongfu; Fan Jie; Xu Lan

2009-01-01

Why do wool fibers show excellent advantages in warmth-retaining and many other practical properties? The paper concludes that their hierarchical structure is the key. Using E-infinity theory, its Hausdorff dimension is estimated to be about 4.2325, very close to El Naschie's E-infinity dimension, 4.2360, revealing an optimal structure for wool fibers.

Roads to infinity the mathematics of truth and proof

CERN Document Server

Stillwell, John C

2010-01-01

Winner of a CHOICE Outstanding Academic Title Award for 2011!This book offers an introduction to modern ideas about infinity and their implications for mathematics. It unifies ideas from set theory and mathematical logic, and traces their effects on mainstream mathematical topics of today, such as number theory and combinatorics. The treatment is historical and partly informal, but with due attention to the subtleties of the subject. Ideas are shown to evolve from natural mathematical questions about the nature of infinity and the nature of proof, set against a background of broader questions

Il Concetto di Infinito nell'Intuizione Matematica (Concept of Infinity in Mathematical Intuition).

Science.gov (United States)

Ferrari, E.; And Others

1995-01-01

Investigated the acquisition and maturation of the infinity concept in mathematics of students ages 13-15. Found the infinity concept is learned by students only when provided with appropriate guidance. (Author/MKR)

Robust output feedback H-infinity control and filtering for uncertain linear systems

CERN Document Server

Chang, Xiao-Heng

2014-01-01

"Robust Output Feedback H-infinity Control and Filtering for Uncertain Linear Systems" discusses new and meaningful findings on robust output feedback H-infinity control and filtering for uncertain linear systems, presenting a number of useful and less conservative design results based on the linear matrix inequality (LMI) technique. Though primarily intended for graduate students in control and filtering, the book can also serve as a valuable reference work for researchers wishing to explore the area of robust H-infinity control and filtering of uncertain systems. Dr. Xiao-Heng Chang is a Professor at the College of Engineering, Bohai University, China.

Solution of the neutron transport equation by means of Hermite-Ssub(infinity)-theory

International Nuclear Information System (INIS)

Brandt, D.; Haelg, W.; Mennig, J.

1979-01-01

A stable numerical approximation Hsub(α)-Ssub(infinity) is obtained through the use of Hermite's method of order α(Hsub(α)) in the spatial integration of the ID neutron transport equation. The theory for α = 1 is applied to a one-group shielding problem. Numerical calculations show the new method to converge much faster than earlier versions of Ssub(infinity)-theory. Comparison of H 1 - Ssub(infinity) with the well-known Ssub(N)-code ANISN indicates a large gain in computing time for the former. (Auth.)

Timelike geodesics around a charged spherically symmetric dilaton black hole

Directory of Open Access Journals (Sweden)

Blaga C.

2015-01-01

Full Text Available In this paper we study the timelike geodesics around a spherically symmetric charged dilaton black hole. The trajectories around the black hole are classified using the effective potential of a free test particle. This qualitative approach enables us to determine the type of orbit described by test particle without solving the equations of motion, if the parameters of the black hole and the particle are known. The connections between these parameters and the type of orbit described by the particle are obtained. To visualize the orbits we solve numerically the equation of motion for different values of parameters envolved in our analysis. The effective potential of a free test particle looks different for a non-extremal and an extremal black hole, therefore we have examined separately these two types of black holes.

Higher spin realization of the DS/CFT correspondence

International Nuclear Information System (INIS)

Anninos, Dionysios; Hartman, Thomas; Strominger, Andrew

2017-01-01

We conjecture that Vasiliev’s theory of higher spin gravity in four-dimensional de Sitter space (dS 4 ) is holographically dual to a three-dimensional conformal field theory (CFT 3 ) living on the spacelike boundary of dS 4 at future timelike infinity. The CFT 3 is the Euclidean Sp ( N ) vector model with anticommuting scalars. The free CFT 3 flows under a double-trace deformation to an interacting CFT 3 in the IR. We argue that both CFTs are dual to Vasiliev dS 4 gravity but with different future boundary conditions on the bulk scalar field. Our analysis rests heavily on analytic continuations of bulk and boundary correlators in the proposed duality relating the O ( N ) model with Vasiliev gravity in AdS 4 . (paper)

Challenges in assessing college students' conception of duality: the case of infinity

Science.gov (United States)

Babarinsa-Ochiedike, Grace Olutayo

Interpreting students' views of infinity posits a challenge for researchers due to the dynamic nature of the conception. There is diversity and variation among students' process-object perceptions. The fluctuations between students' views however reveal an undeveloped duality conception. This study examined college students' conception of duality in understanding and representing infinity with the intent to design strategies that could guide researchers in categorizing students' views of infinity into different levels. Data for the study were collected from N=238 college students enrolled in Calculus sequence courses (Pre-Calculus, Calculus I through Calculus III) at one of the southwestern universities in the U.S. using self-report questionnaires and semi-structured individual task-based interviews. Data was triangulated using multiple measures analyzed by three independent experts using self-designed coding sheets to assess students' externalization of the duality conception of infinity. Results of this study reveal that college students' experiences in traditional Calculus sequence courses are not supportive of the development of duality conception. On the contrary, it strengthens the singularity perspective on fundamental ideas of mathematics such as infinity. The study also found that coding and assessing college students' conception of duality is a challenging and complex process due to the dynamic nature of the conception that is task-dependent and context-dependent. Practical significance of the study is that it helps to recognize misconceptions and starts addressing them so students will have a more comprehensive view of fundamental mathematical ideas as they progress through the Calculus coursework sequence. The developed duality concept development framework called Action-Process-Object-Duality (APOD) adapted from the APOS theory could guide educators and researchers as they engage in assessing students' conception of duality. The results of this study

Binary black hole coalescence in the large-mass-ratio limit: The hyperboloidal layer method and waveforms at null infinity

International Nuclear Information System (INIS)

Bernuzzi, Sebastiano; Nagar, Alessandro; Zenginoglu, Anil

2011-01-01

We compute and analyze the gravitational waveform emitted to future null infinity by a system of two black holes in the large-mass-ratio limit. We consider the transition from the quasiadiabatic inspiral to plunge, merger, and ringdown. The relative dynamics is driven by a leading order in the mass ratio, 5PN-resummed, effective-one-body (EOB), analytic-radiation reaction. To compute the waveforms, we solve the Regge-Wheeler-Zerilli equations in the time-domain on a spacelike foliation, which coincides with the standard Schwarzschild foliation in the region including the motion of the small black hole, and is globally hyperboloidal, allowing us to include future null infinity in the computational domain by compactification. This method is called the hyperboloidal layer method, and is discussed here for the first time in a study of the gravitational radiation emitted by black hole binaries. We consider binaries characterized by five mass ratios, ν=10 -2,-3,-4,-5,-6 , that are primary targets of space-based or third-generation gravitational wave detectors. We show significative phase differences between finite-radius and null-infinity waveforms. We test, in our context, the reliability of the extrapolation procedure routinely applied to numerical relativity waveforms. We present an updated calculation of the final and maximum gravitational recoil imparted to the merger remnant by the gravitational wave emission, v kick end /(cν 2 )=0.04474±0.00007 and v kick max /(cν 2 )=0.05248±0.00008. As a self-consistency test of the method, we show an excellent fractional agreement (even during the plunge) between the 5PN EOB-resummed mechanical angular momentum loss and the gravitational wave angular momentum flux computed at null infinity. New results concerning the radiation emitted from unstable circular orbits are also presented. The high accuracy waveforms computed here could be considered for the construction of template banks or for calibrating analytic models such

Synthesizing mixed H2/H-infinity dynamic controller using evolutionary algorithms

DEFF Research Database (Denmark)

Pedersen, Gerulf; Langballe, A.S.; Wisniewski, Rafal

2001-01-01

This paper covers the design of an Evolutionary Algorithm (EA), which should be able to synthesize a mixed H2/H-infinity. It will be shown how a system can be expressed as Matrix Inequalities (MI) and these will then be used in the design of the EA. The main objective is to examine whether a mixed...... H2/H-infinity controller is feasible, and if so, how the optimal mixed controller might befound....

Robust H(infinity) tracking control of boiler-turbine systems.

Science.gov (United States)

Wu, J; Nguang, S K; Shen, J; Liu, G; Li, Y G

2010-07-01

In this paper, the problem of designing a fuzzy H(infinity) state feedback tracking control of a boiler-turbine is solved. First, the Takagi and Sugeno fuzzy model is used to model a boiler-turbine system. Next, based on the Takagi and Sugeno fuzzy model, sufficient conditions for the existence of a fuzzy H(infinity) nonlinear state feedback tracking control are derived in terms of linear matrix inequalities. The advantage of the proposed tracking control design is that it does not involve feedback linearization technique and complicated adaptive scheme. An industrial boiler-turbine system is used to illustrate the effectiveness of the proposed design as compared with a linearized approach. 2010 ISA. Published by Elsevier Ltd. All rights reserved.

Infinity as a Multi-Faceted Concept in History and in the Mathematics Classroom

Science.gov (United States)

Arzarello, Ferdinando; Bussi, Maria G., Bartolini; Robutti, Ornella

2004-01-01

This paper presents the conceptualisation of infinity as a multi-faceted concept, discussing two examples. The first is from history and illustrates the work of Euler, when using infinity in an algebraic context. The second sketches an activity in a school context, namely students who approach the definite integral with symbolic-graphic…

The pion-nucleon form factor in space- and time-like regions

International Nuclear Information System (INIS)

Speth, J.; Tegen, R.

1990-01-01

We investigate the pion-nucleon vertex function in space- and time-like regions; these vertex functions appear as internal vertices in nucleon-antinucleon annihilations into n pions (n=2, 3, ..., 6). It is emphasised that only relativistic quark models can account for these vertices where one of the baryons/antibaryons is far off-shell with total energy close to zero. Using a novel 4-momentum projection technique we obtain results which generalize the usual (Breit frame) calculation of G πNN (k 2 ) (space-like) thereby removing completely the discrepancy in the Goldberger-Treiman relation. Our relativistic quark model calculation also explains the empirical suppression of antibaryonic contributions to the vertex functions Gsub(πNanti B) and Gsub(πBanti N) which enter in processes like Nanti N→ππ. (orig.)

Comparison of cumulative dissipated energy between the Infiniti and Centurion phacoemulsification systems

Directory of Open Access Journals (Sweden)

Chen M

2015-07-01

Full Text Available Ming Chen,1 Erik Anderson,2 Geoffrey Hill,3 John J Chen,4 Thomas Patrianakos2 1Department of Surgery, University of Hawaii, Honolulu, HI, 2Department of Ophthalmology, John H Stroger, Jr Hospital of Cook County, Chicago, IL, 3Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, 4Biostatistics Core, John A Burns School of Medicine, University of Hawaii, Honolulu, HI, USA Purpose: To compare cumulative dissipated energy between two phacoemulsification machines. Setting: An ambulatory surgical center, Honolulu, Hawaii, USA. Design: Retrospective chart review. Methods: A total of 2,077 consecutive cases of cataract extraction by phacoemulsification performed by five surgeons from November 2012 to November 2014 were included in the study; 1,021 consecutive cases were performed using the Infiniti Vision System, followed by 1,056 consecutive cases performed using the Centurion Vision System. Results: The Centurion phacoemulsification system required less energy to remove a cataractous lens with an adjusted average energy reduction of 38% (5.09 percent-seconds (P<0.001 across all surgeons in comparison to the Infiniti phacoemulsification system. The reduction in cumulative dissipated energy was statistically significant for each surgeon, with a range of 29%–45% (2.25–12.54 percent-seconds (P=0.005–<0.001. Cumulative dissipated energy for both the Infiniti and Centurion systems varied directly with patient age, increasing an average of 2.38 percent-seconds/10 years. Conclusion: The Centurion phacoemulsification system required less energy to remove a cataractous lens in comparison to the Infiniti phacoemulsification system. Keywords: phacoemulsification, cumulative dissipated energy, Centurion Vision System, Infiniti Vision System

Can an observer really catch up with light?

International Nuclear Information System (INIS)

Tian, Guihua; Zheng, Zhao

2003-01-01

Given a null geodesic γ 0 (λ) with a point r in (p, q) conjugate to p along γ 0 (λ), up to the second variation, there will be a variation of γ 0 (λ) which will give a timelike curve from p to q. This is the well-known theory proved in the famous book (Hawking S W and Ellis G F R 1973 The Large Scale Structure of Space-Time (Cambridge: Cambridge University Press)). In this paper, we prove that the timelike curves coming from the above-mentioned second variation have a proper acceleration approaching infinity as the timelike curves approach the null geodesic. This means no observer infinitesimally near the light can begin at the same point with it and finally catch up with it. Only when separated from the light path finitely, can the observer begin at the same point with it and really catch up with it

On the geometry of Riemannian manifolds with a Lie structure at infinity

Directory of Open Access Journals (Sweden)

Bernd Ammann

2004-01-01

Full Text Available We study a generalization of the geodesic spray and give conditions for noncomapct manifolds with a Lie structure at infinity to have positive injectivity radius. We also prove that the geometric operators are generated by the given Lie algebra of vector fields. This is the first one in a series of papers devoted to the study of the analysis of geometric differential operators on manifolds with Lie structure at infinity.

Synthesizing multi-objective H2/H-infinity dynamic controller using evolutionary algorithms

DEFF Research Database (Denmark)

Pedersen, Gerulf; Langballe, A.S.; Wisniewski, Rafal

This paper covers the design of an Evolutionary Algorithm (EA), which should be able to synthesize a mixed H2/H-infinity. It will be shown how a system can be expressed as Matrix Inequalities (MI) and these will then be used in the design of the EA. The main objective is to examine whether a mixed...... H2/H-infinity controller is feasible, and if so, how the optimal mixed controller might befound....

On Closed Timelike Curves and Warped Brane World Models

Directory of Open Access Journals (Sweden)

Slagter Reinoud Jan

2013-09-01

Full Text Available At first glance, it seems possible to construct in general relativity theory causality violating solutions. The most striking one is the Gott spacetime. Two cosmic strings, approaching each other with high velocity, could produce closed timelike curves. It was quickly recognized that this solution violates physical boundary conditions. The effective one particle generator becomes hyperbolic, so the center of mass is tachyonic. On a 5-dimensional warped spacetime, it seems possible to get an elliptic generator, so no obstruction is encountered and the velocity of the center of mass of the effective particle has an overlap with the Gott region. So a CTC could, in principle, be constructed. However, from the effective 4D field equations on the brane, which are influenced by the projection of the bulk Weyl tensor on the brane, it follows that no asymptotic conical space time is found, so no angle deficit as in the 4D counterpart model. This could also explain why we do not observe cosmic strings.

Quantum field theory in spaces with closed time-like curves

International Nuclear Information System (INIS)

Boulware, D.G.

1992-01-01

Gott spacetime has closed timelike curves, but no locally anomalous stress-energy. A complete orthonormal set of eigenfunctions of the wave operator is found in the special case of a spacetime in which the total deficit angle is 27π. A scalar quantum field theory is constructed using these eigenfunctions. The resultant interacting quantum field theory is not unitary because the field operators can create real, on-shell, particles in the acausal region. These particles propagate for finite proper time accumulating an arbitrary phase before being annihilated at the same spacetime point as that at which they were created. As a result, the effective potential within the acausal region is complex, and probability is not conserved. The stress tensor of the scalar field is evaluated in the neighborhood of the Cauchy horizon; in the case of a sufficiently small Compton wavelength of the field, the stress tensor is regular and cannot prevent the formation of the Cauchy horizon

Asymptotic symmetries of Rindler space at the horizon and null infinity

International Nuclear Information System (INIS)

Chung, Hyeyoun

2010-01-01

We investigate the asymptotic symmetries of Rindler space at null infinity and at the event horizon using both systematic and ad hoc methods. We find that the approaches that yield infinite-dimensional asymptotic symmetry algebras in the case of anti-de Sitter and flat spaces only give a finite-dimensional algebra for Rindler space at null infinity. We calculate the charges corresponding to these symmetries and confirm that they are finite, conserved, and integrable, and that the algebra of charges gives a representation of the asymptotic symmetry algebra. We also use relaxed boundary conditions to find infinite-dimensional asymptotic symmetry algebras for Rindler space at null infinity and at the event horizon. We compute the charges corresponding to these symmetries and confirm that they are finite and integrable. We also determine sufficient conditions for the charges to be conserved on-shell, and for the charge algebra to give a representation of the asymptotic symmetry algebra. In all cases, we find that the central extension of the charge algebra is trivial.

A fluidics comparison of Alcon Infiniti, Bausch & Lomb Stellaris, and Advanced Medical Optics Signature phacoemulsification machines.

Science.gov (United States)

Georgescu, Dan; Kuo, Annie F; Kinard, Krista I; Olson, Randall J

2008-06-01

To compare three phacoemulsification machines for measurement accuracy and postocclusion surge (POS) in human cadaver eyes. In vitro comparisons of machine accuracy and POS. Tip vacuum and flow were compared with machine indicated vacuum and flow. All machines were placed in two human cadaver eyes and POS was determined. Vacuum (% of actual) was 101.9% +/- 1.7% for Infiniti (Alcon, Fort Worth, Texas, USA), 93.2% +/- 3.9% for Stellaris (Bausch & Lomb, Rochester, New York, USA), and 107.8% +/- 4.6% for Signature (Advanced Medical Optics, Santa, Ana, California, USA; P Infiniti, 53.5 +/- 0.0 ml/minute and 179.8 +/- 0.9 mm Hg for Stellaris, and 58.5 +/- 0.0 ml/minute and 115.1 +/- 2.3 mm Hg for Signature (P Infiniti, 0.16 +/- 0.06 mm for Stellaris, and 0.13 +/- 0.04 mm for Signature at 550 mm Hg, 60 cm bottle height, 45 ml/minute flow with 19-gauge tips (P Infiniti vs Stellaris and Signature). POS in an 81-year-old eye was 1.51 +/- 0.22 mm for Infiniti, 0.83 +/- 0.06 mm for Stellaris, 0.67 +/- 0.01 mm for Signature at 400 mm Hg vacuum, 70 cm bottle height, 40 ml/minute flow with 19-gauge tips (P Infiniti and Stellaris were similar. Minimizing POS and vacuum to maintain flow potentially are important in avoiding ocular damage and surgical complications.

Instanton geometry and quantum A{sub {infinity}} structure on the elliptic curve

Energy Technology Data Exchange (ETDEWEB)

Herbst, M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Lerche, W. [European Lab. for Particle Physics (CERN), Geneva (Switzerland); Nemeschansky, D. [University of Southern California, Los Angeles, CA (United States). Dept. of Physics

2006-03-15

We first determine and then study the complete set of non-vanishing A-model correlation functions associated with the 'long-diagonal branes' on the elliptic curve. We verify that they satisfy the relevant A{sub {infinity}} consistency relations at both classical and quantum levels. In particular we find that the A{sub {infinity}} relation for the annulus provides a reconstruction of annulus instantons out of disk instantons. We note in passing that the naive application of the Cardy-constraint does not hold for our correlators, confirming expectations. Moreover, we analyze various analytical properties of the correlators, including instanton flops and the mixing of correlators with different numbers of legs under monodromy. The classical and quantum A{sub {infinity}} relations turn out to be compatible with such homotopy transformations. They lead to a non-invariance of the effective action under modular transformations, unless compensated by suitable contact terms which amount to redefinitions of the tachyon fields. (orig.)

Comparison of cumulative dissipated energy between the Infiniti and Centurion phacoemulsification systems.

Science.gov (United States)

Chen, Ming; Anderson, Erik; Hill, Geoffrey; Chen, John J; Patrianakos, Thomas

2015-01-01

To compare cumulative dissipated energy between two phacoemulsification machines. An ambulatory surgical center, Honolulu, Hawaii, USA. Retrospective chart review. A total of 2,077 consecutive cases of cataract extraction by phacoemulsification performed by five surgeons from November 2012 to November 2014 were included in the study; 1,021 consecutive cases were performed using the Infiniti Vision System, followed by 1,056 consecutive cases performed using the Centurion Vision System. The Centurion phacoemulsification system required less energy to remove a cataractous lens with an adjusted average energy reduction of 38% (5.09 percent-seconds) (PInfiniti phacoemulsification system. The reduction in cumulative dissipated energy was statistically significant for each surgeon, with a range of 29%-45% (2.25-12.54 percent-seconds) (P=0.005-Infiniti and Centurion systems varied directly with patient age, increasing an average of 2.38 percent-seconds/10 years. The Centurion phacoemulsification system required less energy to remove a cataractous lens in comparison to the Infiniti phacoemulsification system.

Cosmic infinity: A dynamical system approach

OpenAIRE

Bouhmadi-López, Mariam; Marto, João; Morais, João; Silva, César M.

2016-01-01

Dynamical system techniques are extremely useful to study cosmology. It turns out that in most of the cases, we deal with finite isolated fixed points corresponding to a given cosmological epoch. However, it is equally important to analyse the asymptotic behaviour of the universe. On this paper, we show how this can be carried out for 3-forms model. In fact, we show that there are fixed points at infinity mainly by introducing appropriate compactifications and defining a new time variable tha...

A Passage to Infinity Medieval Indian Mathematics from Kerala and Its Impact

CERN Document Server

Joseph, George Gheverghese

2009-01-01

This book traces the first faltering steps taken in the mathematical theorisation of infinity which marks the emergence of modern mathematics. It analyses the part played by Indian mathematicians through the Kerala conduit, which is an important but neglected part of the history of mathematics. Passage to Infinity: Medieval Indian Mathematics from Kerala and its Impact begins with an examination of the social origins of the Kerala School and proceeds to discuss its mathematical genesis as well as its achievements. It presents the techniques employed by the School to derive the series expansion

Robust Design of H-infinity Controller for a Launch Vehicle Autopilot against Disturbances

OpenAIRE

Graells, Antonio; Carrabina, Francisco

2016-01-01

Atmospheric flight phase of a launch vehicle is utilized to evaluate the performance of an H-infinity controller in the presence of disturbances. Dynamics of the vehicle is linearly modeled using time-varying parameters. An operating point was found to design a robust command tracker using H-infinity control theory that guarantees a stable maneuver. At the end, the controller was employed on the launch vehicle to assess the capability of control design on the linearized aerospace vehicle. Exp...

Proton electromagnetic form factors: present status and future perspectives at PANDA

Directory of Open Access Journals (Sweden)

Tomasi-Gustafsson E.

2015-01-01

Full Text Available Data and models on electromagnetic proton form factors are reviewed, highlighting the contribution foreseen by the PANDA collaboration. Electromagnetic hadron form factors contain essential information on the internal structure of hadrons. Precise and surprising data have been obtained at electron accelerators, applying the polarization method in electron-proton elastic scattering. At electron-positron colliders, using initial state radiation, BABAR measured proton time-like form factors in a wide time-like kinematical region and the BESIII collaboration will measure very precisely proton and neutron form factors in the threshold region. In the next future an antiproton beam with momentum up to 15 GeV/c will be available at FAIR (Darmstadt. Measurements of the reaction p̅ + p → e+ + e− by the PANDA collaboration will contribute to the individual determination of electric and magnetic form factors in the time-like region of momentum transfer squared, as well as to their first determination in the unphysical region (below the kinematical threshold, through the reaction p̅ + p → e+ + e− + π0. From the discussion on feasibility studies at PANDA, we focus on the consequences of such measurements in view of an unified description of form factors in the full kinematical region. We present models which have the necessary analytical requirements and apply to the data in the whole kinematical region.

Gauge theories on the lattice at N/sub c/ = infinity

International Nuclear Information System (INIS)

Cristofano, G.A.

1982-01-01

The thesis is devoted to the study of the physical properties of the SU(N/sub c/) Yang Mills theory on the lattice at N/sub c/ = infinity. Since the lattice approach provides a natural framework toward a better understanding of nonperturbative phenomena, like quark confinement, nonperturbative physical quantities, like the string tension and the glueball mass are studied. The first two chapters are introductory in nature. In chapters (3,4) the strong coupling expansion for the Euclidean SU(N/sub c/) lattice gauge theory at N/sub c/ = infinity to 16th and 12th order in β = 1/g 0 2 N/sub c/ for the free energy F and the string tension k respectively is performed. Estimates of the ratio √k/Λ/sub L/ and of the crossover point from strong to weak coupling for the string tension are made by matching the strong coupling series to the asymptotically free continuum theory. In chapter (5) the strong coupling expansion for the glueball mass m/sub g/ to the 8th order in β for the Euclidean SU(infinity) lattice gauge theory is performed. The ratio of the glueball mass m/sub g/ to the squareroot of the string tension √k for the SU(infinity) theory is estimated to be m/sub g//√k = 2.6 +/- 0.2. It is found that the ratio m/sub g//√k has a rather small dependence on N/sub c/ and appears to increase with the number of colors N/sub c/. In chapter (6) two-point Pade approximants for the one plaquette expectation value E/sub p/ for the SU(2) lattice gauge theory by using the known strong and weak coupling series for D/sub p/ is performed. Comparison with the correspondent Monte Carlo results is made, especially in the delicate transition region, at intermediate β = 4/g 0 2

INFINITY at NASA Stennis Space Center

Science.gov (United States)

2010-01-01

Flags are planted on the roof of the new INFINITY at NASA Stennis Space Center facility under construction just west of the Mississippi Welcome Center at exit 2 on Interstate 10. Stennis and community leaders celebrated the 'topping out' of the new science center Nov. 17, marking a construction milestone for the center. The 72,000-square-foot science and education center will feature space and Earth galleries to showcase the science that underpins the missions of the agencies at Stennis Space Center. The center is targeted to open in 2012.

Exceptional Lie groups, E-infinity theory and Higgs Boson

International Nuclear Information System (INIS)

El-Okaby, Ayman A.

2008-01-01

In this paper we study the correlation between El-Naschie's exceptional Lie groups hierarchies and his transfinite E-infinity space-time theory. Subsequently this correlation is used to calculate the number of elementary particles in the standard model, mass of the Higgs Bosons and some coupling constants

Hypersonic vehicle control law development using H(infinity) and micron-synthesis

Science.gov (United States)

Gregory, Irene M.; Mcminn, John D.; Shaughnessy, John D.; Chowdhry, Rajiv S.

1993-01-01

Hypersonic vehicle control law development using H(infinity) and mu-synthesis is discussed. Airbreathing SSTO vehicles has a mutli-faceted mission that includes orbital operations, as well as re-entry and descent culminating in horizontal landing. However, the most challenging part of the operations is the ascent to orbit. The airbreathing propulsion requires lengthy atmospheric flight that may last as long as 30 minutes and take the vehicle half way around the globe. The vehicles's ascent is characterized by tight payload to orbit margins which translate into minimum fuel orbit as the performance criteria. Issues discussed include: SSTO airbreathing vehicle issues; control system performance requirements; robust control law framework; H(infinity) controller frequency analysis; and mu controller frequency analysis.

Eliminating infinities in the λφ4 theory by simple scaling

International Nuclear Information System (INIS)

Aragao, Cristiane M.L. de; Carneiro, C.E.I.

2006-01-01

We present an alternative method to remove infinities in the perturbative φ 4 theory. In our method, the renormalization is performed in two stages. Firstly, the infinities are eliminated by rescaling the Lagrangian. The Green functions obtained from this rescaled Lagrangian are finite to all orders in perturbation. Secondly, we fix the values of parameters of the resulting finite theory at a certain mass scale by using the standard renormalization conditions. This second stage allows us to derive renormalization equations which yields the critical behavior of the theory. We show that our method does not change the critical behavior of the λφ 4 theory in 4-ε dimensions. In particular, we recover the usual critical exponents

A New Adaptive H-Infinity Filtering Algorithm for the GPS/INS Integrated Navigation

Science.gov (United States)

Jiang, Chen; Zhang, Shu-Bi; Zhang, Qiu-Zhao

2016-01-01

The Kalman filter is an optimal estimator with numerous applications in technology, especially in systems with Gaussian distributed noise. Moreover, the adaptive Kalman filtering algorithms, based on the Kalman filter, can control the influence of dynamic model errors. In contrast to the adaptive Kalman filtering algorithms, the H-infinity filter is able to address the interference of the stochastic model by minimization of the worst-case estimation error. In this paper, a novel adaptive H-infinity filtering algorithm, which integrates the adaptive Kalman filter and the H-infinity filter in order to perform a comprehensive filtering algorithm, is presented. In the proposed algorithm, a robust estimation method is employed to control the influence of outliers. In order to verify the proposed algorithm, experiments with real data of the Global Positioning System (GPS) and Inertial Navigation System (INS) integrated navigation, were conducted. The experimental results have shown that the proposed algorithm has multiple advantages compared to the other filtering algorithms. PMID:27999361

How some infinities cause problems in classical physical theories

NARCIS (Netherlands)

Atkinson, David; Peijnenburg, Jeanne; Allo, P.; van Kerhove, B.

2014-01-01

In this paper we review a 1992 excursion of Jean Paul Van Bendegem into physics, ‘How Infinities Cause Problems in Classical Physical Theories’, in the light of two later models concerning colliding balls, of Pérez Laraudogoitia and of Alper and Bridger, respectively. We show that Van Bendegem

Computing Gowdy spacetimes via spectral evolution in future and past directions

International Nuclear Information System (INIS)

Amorim, Paulo; Bernardi, Christine; LeFloch, Philippe G

2009-01-01

We consider a system of nonlinear wave equations with constraints that arises from the Einstein equations of general relativity and describes the geometry of the so-called Gowdy symmetric spacetimes on T 3 . We introduce two numerical methods, which are based on the pseudo-spectral approximation. The first approach relies on marching in the future timelike direction and toward the singularity t = 0 and is based on a novel nonlinear transformation, which allows us to reduce the nonlinear source terms to simple quadratic products of the unknown variables. The second approach is designed from asymptotic formulae that are available near this singularity, and evolves the solutions in the past timelike direction from the 'final' data given at t = 0. Numerical experiments are presented in various regimes, including cases where 'spiky' structures are observed as the singularity is approached. The proposed backward strategy leads to a robust numerical method which allows us to accurately simulate the long-time behavior of a large class of Gowdy spacetimes.

Bound states for square well potentials extending to infinity in D ≥ 2

International Nuclear Information System (INIS)

Rupertsberger, H.

1992-01-01

It is well known that quantum mechanics allows the penetration into classically forbidden regions (tunneling). Less well known seems to be the fact that in some sense the converse is true also. Potentials with classically allowed regions where a particle can move freely to infinity can nevertheless lead to bound states in quantum mechanics due to the stringent requirements of the boundary conditions, thus forbidding an escape to infinity. This effect is demonstrated by using an obvious generalization of the well known one-dimensional (D = 1) square well potential to arbitray space dimensions. (author)

SU-E-T-119: Dosimetric and Mechanical Characteristics of Elekta Infinity LINAC with Agility MLC

International Nuclear Information System (INIS)

Park, J; Xu, Q; Xue, J; Zhai, Y; An, L; Chen, Y

2014-01-01

Purpose: Elekta Infinity is the one of the latest generation LINAC with unique features. Two Infinity LINACs are recently commissioned at our institution. The dosimetric and mechanical characteristics of the machines are presented. Methods: Both Infinity LINACs with Agility MLC (160 leaves with 0.5 cm leaf width) are configured with five electron energies (6, 9, 12, 15, and 18 MeV) and two photon energies (6 and 15 MV). One machine has additional photon energy (10 MV). The commissioning was performed by following the manufacturer's specifications and AAPM TG recommendations. Beam data of both electron and photon beams are measured with scanning ion chambers and linear diode array. Machines are adjusted to have the dosimetrically equivalent characteristics. Results: The commissioning of mechanical and imaging system meets the tolerances by TG recommendations. The PDD 10 of various field sizes for 6 and 15 MV shows < 0.5% difference between two machines. For each electron beams, R 80 matches with < 0.4 mm difference. The symmetry and flatness agree within 0.8% and 0.9% differences for photon beams, respectively. For electron beams, the differences of the symmetry and flatness are within 1.2% and 0.8%, respectively. The mean inline penumbras for 6, 10, and 15 MV are respectively 5.1±0.24, 5.6±0.07, and 5.9±0.10 mm for 10x10 cm at 10 cm depth. The crossline penumbras are larger than inline penumbras by 2.2, 1.4, and 1.0 mm, respectively. The MLC transmission factor with interleaf leakage is 0.5 % for all photon energies. Conclusion: The dosimetric and mechanical characteristics of two Infinity LINACs show good agreements between them. Although the Elekta Infinity has been used in many institutions, the detailed characteristics of the machine have not been reported. This study provides invaluable information to understand the Infinity LINAC and to compare the quality of commissioning data for other LINACs

Exponential H(infinity) synchronization of general discrete-time chaotic neural networks with or without time delays.

Science.gov (United States)

Qi, Donglian; Liu, Meiqin; Qiu, Meikang; Zhang, Senlin

2010-08-01

This brief studies exponential H(infinity) synchronization of a class of general discrete-time chaotic neural networks with external disturbance. On the basis of the drive-response concept and H(infinity) control theory, and using Lyapunov-Krasovskii (or Lyapunov) functional, state feedback controllers are established to not only guarantee exponential stable synchronization between two general chaotic neural networks with or without time delays, but also reduce the effect of external disturbance on the synchronization error to a minimal H(infinity) norm constraint. The proposed controllers can be obtained by solving the convex optimization problems represented by linear matrix inequalities. Most discrete-time chaotic systems with or without time delays, such as Hopfield neural networks, cellular neural networks, bidirectional associative memory networks, recurrent multilayer perceptrons, Cohen-Grossberg neural networks, Chua's circuits, etc., can be transformed into this general chaotic neural network to be H(infinity) synchronization controller designed in a unified way. Finally, some illustrated examples with their simulations have been utilized to demonstrate the effectiveness of the proposed methods.

Asymptotics and continuity properties near infinity of solutions of Schroedinger equation in exterior domains

International Nuclear Information System (INIS)

Hoffmann-Ostenhof, M.; Hoffmann-Ostenhof, T.; Swetina, J.

1986-01-01

Let (- Δ + V 1 - E) psi = 0 in Ωsub(R) = (x is an element of Rsup(n)| |x| > R), psi is an element of L 2 (Ωsub(R)), where E 1 (|x|) + V 2 (|x|) with V 1 , V 2 tending to zero for |x| → infinity and satisfying suitable regularity assumption. Further let (- Δ + V 2 (|x|) - E) v(|x|) = 0 for |x| > R where v > 0 and v → 0 for |x| → infinity. Previous results on the asymptotics on psi/v for n = 2 are here extended to the n-dimensional case: It is shown that psi/v (|x| x/|x|) satisfies certain regularity properties uniformly for |x| → infinity as a map from Ssup(n-1) to R. Furthermore using a certain scaling it is shown that the asymptotic behaviour of psi/v can be characterized by eigenfunctions of the isotropic (n-1)-dimensional harmonic oscillator. (Author)

A membrane wave equation for Q.C.D. (SU(infinity))

International Nuclear Information System (INIS)

Botelho, L.C.L.

1988-01-01

It is proposed a quantum membrane wave functional describing the interaction between a colored SU(N c ) membrane and a quantized Yang-Mills field. Additionally, its associated wave equation in the t'Hooft N c ->infinity limit is deduced. (A.C.A.S.) [pt

H-infinity Control of Linear Systems with Almost Periodic Inputs

DEFF Research Database (Denmark)

Larsen, Mikael

1996-01-01

In this paper we consider the class of linear, infinitedimensional systems with bounded input and output operators. Wederive and QTR H-infinity type result, formulated for thecase where the input signals are almost periodic in a generalizedsense. Control probelms, for which this result is relevant...

A new approach to mixed H2/H infinity controller synthesis using gradient-based parameter optimization methods

Science.gov (United States)

Ly, Uy-Loi; Schoemig, Ewald

1993-01-01

In the past few years, the mixed H(sub 2)/H-infinity control problem has been the object of much research interest since it allows the incorporation of robust stability into the LQG framework. The general mixed H(sub 2)/H-infinity design problem has yet to be solved analytically. Numerous schemes have considered upper bounds for the H(sub 2)-performance criterion and/or imposed restrictive constraints on the class of systems under investigation. Furthermore, many modern control applications rely on dynamic models obtained from finite-element analysis and thus involve high-order plant models. Hence the capability to design low-order (fixed-order) controllers is of great importance. In this research a new design method was developed that optimizes the exact H(sub 2)-norm of a certain subsystem subject to robust stability in terms of H-infinity constraints and a minimal number of system assumptions. The derived algorithm is based on a differentiable scalar time-domain penalty function to represent the H-infinity constraints in the overall optimization. The scheme is capable of handling multiple plant conditions and hence multiple performance criteria and H-infinity constraints and incorporates additional constraints such as fixed-order and/or fixed structure controllers. The defined penalty function is applicable to any constraint that is expressible in form of a real symmetric matrix-inequity.

VHTRC experiment for verification test of H{infinity} reactivity estimation method

Energy Technology Data Exchange (ETDEWEB)

Fujii, Yoshio; Suzuki, Katsuo; Akino, Fujiyoshi; Yamane, Tsuyoshi; Fujisaki, Shingo; Takeuchi, Motoyoshi; Ono, Toshihiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1996-02-01

This experiment was performed at VHTRC to acquire the data for verifying the H{infinity} reactivity estimation method. In this report, the experimental method, the measuring circuits and data processing softwares are described in details. (author).

H{sub 2}/H{infinity} control of flexible structures through linear matrix inequalities with pole placement

Energy Technology Data Exchange (ETDEWEB)

Lopes, Jean C. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

2009-07-01

The objective of this work is to apply the H2/H{infinity} control technique using linear matrix inequalities and pole placement constraints to the flexible structures control problem. The H2/H{infinity}control is a technique to design a controller with mixed features of the H2 and H{infinity} control formulations, such as, optimal dynamical performance and robust performance. The Linear Matrix Inequalities allow formulating the problem as a convex optimization problem, and additional constraints can be included such as the pole placement. The pole placement requirement comes from the necessity of adjusting the transient response of the plant and ensuring a specific behavior in terms of speed and damping responses. The mathematical model used for this study is related to a flexible beam, with an applied disturbance and an actuator in different positions. The state-space matrices of the structure were obtained using the finite element method with the Euler-Bernoulli formulation of beams. The results showed that the pole placement constraints can improve the performance of the controller H2/H{infinity}. The Matlab was used for the computational implementation. (author)

Development of homotopy algorithms for fixed-order mixed H2/H(infinity) controller synthesis

Science.gov (United States)

Whorton, M.; Buschek, H.; Calise, A. J.

1994-01-01

A major difficulty associated with H-infinity and mu-synthesis methods is the order of the resulting compensator. Whereas model and/or controller reduction techniques are sometimes applied, performance and robustness properties are not preserved. By directly constraining compensator order during the optimization process, these properties are better preserved, albeit at the expense of computational complexity. This paper presents a novel homotopy algorithm to synthesize fixed-order mixed H2/H-infinity compensators. Numerical results are presented for a four-disk flexible structure to evaluate the efficiency of the algorithm.

On the ideal low-frequency spatial filtration of the electrical potential at infinity

International Nuclear Information System (INIS)

Gluskin, Emanuel

2005-01-01

It is proved that for any physical system with localized voltage input the potential at infinity is the arithmetic average of the given input potentials. This is relevant to the topic of grounding of a system. In terms of spatial filtering, which is becoming a more and more important concept in modern system theory, we have here ideal filtration of the dc component of the (spatial) input voltage 'signal' (i.e., the set of the given input potentials) at 'infinity' considered as the 'filter's output'. A symmetry argument, helpful in numerical simulations, is considered. Some basic system-theory terms, important for the physical side, are carefully defined

Decentralized H-infinity control of complex systems with delayed feedback

Czech Academy of Sciences Publication Activity Database

Bakule, Lubomír; Rehák, Branislav; Papík, Martin

2016-01-01

Roč. 67, č. 1 (2016), s. 127-131 ISSN 0005-1098 R&D Projects: GA ČR GA13-02149S Institutional support: RVO:67985556 Keywords : decentralized control * H-infinity control * large-scale systems * Fault-tolerant systems Subject RIV: BC - Control Systems Theory Impact factor: 5.451, year: 2016

On the topological ground state of E-infinity spacetime and the super string connection

International Nuclear Information System (INIS)

El Naschie, M.S.

2007-01-01

There are at present a huge number of valid super string ground states, making the one corresponding to our own universe extremely hard to determine. Therefore it may come as quite a surprise that it is a rather simple undertaking to determine the exact topological ground state of E-infinity Cantorian spacetime theory. Similar to the ground state of the Higgs for E-infinity, the expectation value of the topological ground state is non-zero and negative. Its value is given exactly by -bar o -∼ n(1/φ) n =-(4+φ 3 ) where φ=(5-1)/2 and n represents an integer Menger-Uhryson dimension running from n=0 to n=-∼. Recalling that the average dimension of ε (∼) is given by ∼ =4+φ 3 , one could interpret this result as saying that our E-infinity spacetime may be viewed as an in itself closed manifold given by the remarkable equation: + =zeroThus in a manner of speaking, the universe could have spontaneously tunnelled into existence from virtual nothingness

Application of an H-infinity based FDI and control scheme for the three tank system

DEFF Research Database (Denmark)

Stoustrup, Jakob; Niemann, H.

2000-01-01

The three tank benchmark system is considered in this paper in connection with combined feedback control and fault detection and identification (FDI). The combined design problem is formulated as an H-infinity design problem by using a standard system setup......The three tank benchmark system is considered in this paper in connection with combined feedback control and fault detection and identification (FDI). The combined design problem is formulated as an H-infinity design problem by using a standard system setup...

Elasto-plastic torsion problem as an infinity Laplace's equation

Directory of Open Access Journals (Sweden)

Ahmed Addou

2006-12-01

Full Text Available In this paper, we study a perturbed infinity Laplace's equation, the perturbation corresponds to an Leray-Lions operator with no coercivity assumption. We consider the case where data are distributions or $L^{1}$ elements. We show that this problem has an unique solution which is the solution to the variational inequality arising in the elasto-plastic torsion problem, associated with an operator $A$.

Thermal imaging comparison of Signature, Infiniti, and Stellaris phacoemulsification systems

OpenAIRE

Ryoo, NK; Kwon, J-W; Wee, WR; Miller, KM; Han, YK

2013-01-01

Abstract Background To compare the heat production of 3 different phacoemulsification machines under strict laboratory test conditions. More specifically, the thermal behavior was analyzed between the torsional modality of the Infiniti system and longitudinal modalities of the Abbot WhiteStar Signature Phacoemulsification system and Bausch and Lomb Stellaris system. Methods Experiments were performed under in-...

Scattering matrix for magnetic potentials with Coulomb decay at infinity

CERN Document Server

Yafaev, D

2003-01-01

We consider the Schr\\"odinger operator $H$ in the space $L_2({\\R}^d)$ with a magnetic potential $A(x)$ decaying as $|x|^{-1}$ at infinity and satisfying the transversal gauge condition $ =0$. Such potentials correspond, for example, to magnetic fields $B(x)$ with compact support and hence are quite general. Our goal is to study properties of the scattering matrix $S(\\lambda)$ associated to the operator $H$. In particular, we find the essential spectrum $\\sigma_{ess}$ of $S(\\lambda)$ in terms of the behaviour of $A(x)$ at infinity. It turns out that $\\sigma_{ess}(S(\\lambda))$ is normally a rich subset of the unit circle ${\\Bbb T}$ or even coincides with ${\\Bbb T}$. We find also the diagonal singularity of the scattering amplitude (of the kernel of $S(\\lambda)$ regarded as an integral operator). In general, $S(\\lambda)$ is a sum of a multiplication operator and of a singular integral operator. However, if the magnetic field decreases faster than $ |x|^{-2}$ for $d\\geq 3$ (and the total magnetic flux is an integ...

COSY INFINITY version 6

International Nuclear Information System (INIS)

Berz, Martin

1993-01-01

COSY INFINITY is an arbitrary order map code for the design and analysis of particle optical systems. It is based on differential algebraic methods, which provide an efficient and elegant framework for typical tasks faced in practice. As the user interface, COSY employs a structured object oriented language, which is simultaneously used for the coding of the physics. This approach allows a seamless connection of the work of the user with the tools provided by the code and directly allows the adaptation of the code to specific tasks. Optimization and fitting is supported at the language level, allowing rather direct and general optimization of essentially any quantity. Lattices can be described in terms of COSY's language environment or alternatively in the standard MAD input. For the sake of portability, the language interface of Cosy is standard FORTRAN 77: the compiler and executer of COSY as well as the libraries to which the language links are all written in this language. The language environment supports a variety of interactive and printer or plotter-based graphics drivers, and new drivers are added easily. (Author)

On the topology of the Newton boundary at infinity

International Nuclear Information System (INIS)

Pham Tien Son

2007-07-01

We will be interested in a global version of Le-Ramanujam μ -constant theorem from the Newton polyhedron point of view. More precisely, we prove a stability theorem which says that the global monodromy fibration of a polynomial with Newton non-degenerate is uniquely determined by its Newton boundary at infinity. Besides, the continuity of atypical values for a family of complex polynomial functions also is considered. (author)

An evolution infinity Laplace equation modelling dynamic elasto-plastic torsion

Science.gov (United States)

Messelmi, Farid

2017-12-01

We consider in this paper a parabolic partial differential equation involving the infinity Laplace operator and a Leray-Lions operator with no coercitive assumption. We prove the existence and uniqueness of the corresponding approached problem and we show that at the limit the solution solves the parabolic variational inequality arising in the elasto-plastic torsion problem.

H{infinity} Filtering for Dynamic Compensation of Self-Powered Neutron Detectors - A Linear Matrix Inequality Based Method -

Energy Technology Data Exchange (ETDEWEB)

Park, M.G.; Kim, Y.H.; Cha, K.H.; Kim, M.K. [Korea Electric Power Research Institute, Taejon (Korea)

1999-07-01

A method is described to develop and H{infinity} filtering method for the dynamic compensation of self-powered neutron detectors normally used for fixed incore instruments. An H{infinity} norm of the filter transfer matrix is used as the optimization criteria in the worst-case estimation error sense. Filter modeling is performed for both continuous- and discrete-time models. The filter gains are optimized in the sense of noise attenuation level of H{infinity} setting. By introducing Bounded Real Lemma, the conventional algebraic Riccati inequalities are converted into Linear Matrix Inequalities (LMIs). Finally, the filter design problem is solved via the convex optimization framework using LMIs. The simulation results show that remarkable improvements are achieved in view of the filter response time and the filter design efficiency. (author). 15 refs., 4 figs., 3 tabs.

Bifurcation from infinity and nodal solutions of quasilinear elliptic differential equations

Directory of Open Access Journals (Sweden)

Bian-Xia Yang

2014-01-01

Full Text Available In this article, we establish a unilateral global bifurcation theorem from infinity for a class of $N$-dimensional p-Laplacian problems. As an application, we study the global behavior of the components of nodal solutions of the problem $$\\displaylines{ \\operatorname{div}(\\varphi_p(\

Semiclassical asymptotics for the scattering amplitude in the presence of focal points at infinity

Energy Technology Data Exchange (ETDEWEB)

Hohberger, H.

2006-10-16

We consider scattering in R{sup n}, n{>=}2, described by the Schroedinger operator P(h)=-h{sup 2}{delta}+V, where V is a short-range potential. With the aid of Maslov theory, we give a geometrical formula for the semiclassical asymptotics as h{yields}0 of the scattering amplitude f({omega}{sub -},{omega}{sub +};{lambda},h) ({omega}{sub +}{ne}{omega}{sub -}) which remains valid in the presence of focal points at infinity (caustics). Crucial for this analysis are precise estimates on the asymptotics of the classical phase trajectories and the relationship between caustics in euclidean phase space and caustics at infinity. (orig.)

Scalar fields in black hole spacetimes

Science.gov (United States)

Thuestad, Izak; Khanna, Gaurav; Price, Richard H.

2017-07-01

The time evolution of matter fields in black hole exterior spacetimes is a well-studied subject, spanning several decades of research. However, the behavior of fields in the black hole interior spacetime has only relatively recently begun receiving some attention from the research community. In this paper, we numerically study the late-time evolution of scalar fields in both Schwarzschild and Kerr spacetimes, including the black hole interior. We recover the expected late-time power-law "tails" on the exterior (null infinity, timelike infinity, and the horizon). In the interior region, we find an interesting oscillatory behavior that is characterized by the multipole index ℓ of the scalar field. In addition, we also study the extremal Kerr case and find strong indications of an instability developing at the horizon.

Computational aspects of optics design and simulation: COSY INFINITY

International Nuclear Information System (INIS)

Berz, M.; National Superconducting Cyclotron Lab., East Lansing, MI; Lawrence Berkeley Lab., CA

1990-01-01

The new differential algebraic (DA) techniques allow very efficient treatment and understanding of nonlinear motion in optical systems aws well as circular accelerators. To utilize these techniques in their most general way, a powerful software environment is essential. A language with structure elements similar to Pascal was developed. It has object oriented features to allow for a direct utilization of the elementary operations of the DA package. The compiler of the language is written in Fortran 77 to guarantee wide portability. The language was used to write a very general beam optics code, COSY INFINITY. At its lowest level, it allows the computation of the maps of standard beam line elements including fringe fields and system parameters to arbitrary order. the power of the DA approach coupled with an adequate language environment reveals itself in the very limited lenth of COSY INFINITY of only a few hundred lines. Grouping of elements as well as structures for optimization and study are readily available through the features of the language. Because of the openness of the approach, it offers a lot of power for more advanced purposes. For example, it is very easy to construct new particle optical elements. There are many ways to efficiently manipulate and analyze the maps. (orig.)

Definitions of black holes without use of the boundary at infinity

International Nuclear Information System (INIS)

Krolak, A.

1982-01-01

Two definitions of a black hole are given without reference to the boundary at infinity of space-time. One definition does not require any global causality condition and the other is applicable to a closed Friedmann-like space-time. The area theorem is found to hold in both cases. (author)

Towards H-infinity Control of an SI Engine's A/F Ratio

DEFF Research Database (Denmark)

Vigild, Christian; Struwe, Michael; Andersen, Karsten

1999-01-01

in conjunction with a PI feedback from a HEGO sensor. The effective bandwidth of this feedback loop is quite small, generally around 2 Hz. This is altogether too small for accurate AFR control.This paper presents a new lambda control methodology (H-infinity) which has a somewhat larger bandwidth and can...

Measurement of the pion form factor in the time-like region for q2 values between 0.1 (GeV/c)2 and 0.18 (GeV/c)2

International Nuclear Information System (INIS)

Amendolia, S.R.; Badelek, B.; Bertolucci, E.; Bettoni, D.; Bizzeti, A.; Bosisio, L.; Bradaschia, C.; Dell'Orso, M.; Foa, L.; Focardi, E.; Giannetti, P.; Giazotto, A.; Giorgi, M.A.; Marrocchesi, P.S.; Menzione, A.; Ristori, L.; Scribano, A.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Frank, S.G.F.; Harvey, J.; Menasce, D.; Meroni, E.; Moroni, L.; Milan Univ.

1984-01-01

The EM form factor of the pion has been studied in the time-like region by measuring sigma(e + e - ->π + π - ) normalization to sigma(e + e - ->μ + μ - ). Results have been obtained for q 2 down to the physical threshold. (orig.)

Cosmic infinity: a dynamical system approach

Energy Technology Data Exchange (ETDEWEB)

Bouhmadi-López, Mariam; Marto, João [Departamento de Física, Universidade da Beira Interior, Rua Marquês D' Ávila e Bolama, 6201-001 Covilhã (Portugal); Morais, João [Department of Theoretical Physics, University of the Basque Country UPV/EHU, P.O. Box 644, 48080 Bilbao (Spain); Silva, César M., E-mail: mbl@ubi.pt, E-mail: jmarto@ubi.pt, E-mail: jviegas001@ikasle.ehu.eus, E-mail: csilva@ubi.pt [Centro de Matemática e Aplicações da Universidade da Beira Interior (CMA-UBI), Rua Marquês D' Ávila e Bolama, 6201-001 Covilhã (Portugal)

2017-03-01

Dynamical system techniques are extremely useful to study cosmology. It turns out that in most of the cases, we deal with finite isolated fixed points corresponding to a given cosmological epoch. However, it is equally important to analyse the asymptotic behaviour of the universe. On this paper, we show how this can be carried out for 3-form models. In fact, we show that there are fixed points at infinity mainly by introducing appropriate compactifications and defining a new time variable that washes away any potential divergence of the system. The richness of 3-form models allows us as well to identify normally hyperbolic non-isolated fixed points. We apply this analysis to three physically interesting situations: (i) a pre-inflationary era; (ii) an inflationary era; (iii) the late-time dark matter/dark energy epoch.

Comparison of cumulative dissipated energy between the Infiniti and Centurion phacoemulsification systems [Corrigendum

Directory of Open Access Journals (Sweden)

Chen M

2015-08-01

Full Text Available Chen M, Anderson E, Hill G, et al. Clin Ophthalmol. 2015;9:1367–1372.  On page 1367, the final sentence of the Introduction which reads:  “The purpose of this study was simply to compare the CDE between the single Centurion and single Infiniti phacoemulsification systems in a larger number of cases to see which one uses less CDE under similar age, sex, and complication rate (P>0.05 among five surgeons in one surgical center.”    Should read:“The purpose of this study is to compare the mean CDE and complication rate of the Centurion and Infiniti phacoemulsification systems.”On page 1370 there were errors in both Figures 1 and 2. The correct figures are presented here. Read the original article

Design and Implement a Digital H{sub {infinity}}Robust Controller for a MW-Class PMSG-Based Grid-Interactive Wind Energy Conversion System

Energy Technology Data Exchange (ETDEWEB)

Howlander, Abdul Motin [Faculty of Engineering, Univ. of the Ryukyus, Okinawa (Japan); Urasaki, Naomitsu [Faculty of Engineering, Univ. of the Ryukyus, Okinawa (Japan); Yona, Atsushi [Faculty of Engineering, Univ. of the Ryukyus, Okinawa (Japan); Senjyu, Tomonobu [Faculty of Engineering, Univ. of the Ryukyus, Okinawa (Japan); Saber, Ahmed Yousuf [Operation Technology, Irvine, CA (United States)

2013-04-15

A digital H{sub {infinity}}controller for a permanent magnet synchronous generator (PMSG) based wind energy conversion system (WECS) is presented. Wind energy is an uncertain fluctuating resource which requires a tight control management. So, it is still an exigent task for the control design engineers. The conventional proportional-integral (PI) control is not ideal during high turbulence wind velocities, and the nonlinear behavior of the power converters. These are raising interest towards the robust control concepts. The robust design is to find a controller, for a given system, such that the closed-loop system becomes robust that assurance high-integrity and fault tolerant control system, robust H{sub {infinity}}control theory has befallen a standard design method of choice over the past two decades in industrial control applications. The robust H{sub {infinity}}control theory is also gaining eminence in the WECS. Due to the implementation complexity for the continuous H{sub {infinity}}controller, and availability of the high speedy micro-controllers, the design of a sample-data or a digital H{sub {infinity}}controller is very important for the realistic implementation. But there isn’t a single research to evaluate the performance of the digital H{sub {infinity}}controller for the WECS. In this paper, the proposed digital H{sub {infinity}}controller schemes comprise for the both generator and grid interactive power converters, and the control performances are compared with the conventional PI controller and the fuzzy controller. Simulation results confirm the efficacy of the proposed method Energies 2013, 6 2085 which are ensured the WECS stabilities, mitigate shaft stress, and improving the DC-link voltage and output power qualities.

Infinities in Quantum Field Theory and in Classical Computing: Renormalization Program

Science.gov (United States)

Manin, Yuri I.

Introduction. The main observable quantities in Quantum Field Theory, correlation functions, are expressed by the celebrated Feynman path integrals. A mathematical definition of them involving a measure and actual integration is still lacking. Instead, it is replaced by a series of ad hoc but highly efficient and suggestive heuristic formulas such as perturbation formalism. The latter interprets such an integral as a formal series of finite-dimensional but divergent integrals, indexed by Feynman graphs, the list of which is determined by the Lagrangian of the theory. Renormalization is a prescription that allows one to systematically "subtract infinities" from these divergent terms producing an asymptotic series for quantum correlation functions. On the other hand, graphs treated as "flowcharts", also form a combinatorial skeleton of the abstract computation theory. Partial recursive functions that according to Church's thesis exhaust the universe of (semi)computable maps are generally not everywhere defined due to potentially infinite searches and loops. In this paper I argue that such infinities can be addressed in the same way as Feynman divergences. More details can be found in [9,10].

Axisymmetric Electrovacuum Spacetimes with AN Additional Killing Vector and Radiation

Science.gov (United States)

Pravdová, A.; Bičák, J.

2002-12-01

In the present note we briefly summarize our recent work [1, 2] on possible additional symmetries of axially symmetric electrovacuum spacetimes which admit radiation. The main result states that only boost and rotation (axially) symmetric electrovacuum spacetimes can be radiative and asymptotically flat at null infinity {J} which admits global sections. If an additional symmetry is a translational spacelike or null Killing field the spacetime represents cylindrical or plane-type waves, local {J} may still exist but some of its generators are missing. Boost-rotation symmetric spacetimes are the only known exact explicit radiative solutions of Einstein's equations describing moving objects - singularities or black holes uniformly accelerated along the axis of symmetry. They are radiative and admit a smooth {J} although at least four points of {J} are missing. They represent the only known examples in which arbitrarily strong initial data with the given symmetry can be chosen on a hyperboloidal hypersurface which evolve into a complete, smooth null infinity and regular timelike infinity. For the latest reviews, containing a number of relevant references, see [3, 4]...

Electrostatic potential map modelling with COSY Infinity

International Nuclear Information System (INIS)

Maloney, J.A.; Baartman, R.; Planche, T.; Saminathan, S.

2016-01-01

COSY Infinity (Makino and Berz, 2005) is a differential-algebra based simulation code which allows accurate calculation of transfer maps to arbitrary order. COSY’s existing internal procedures were modified to allow electrostatic elements to be specified using an array of field potential data from the midplane. Additionally, a new procedure was created allowing electrostatic elements and their fringe fields to be specified by an analytic function. This allows greater flexibility in accurately modelling electrostatic elements and their fringe fields. Applied examples of these new procedures are presented including the modelling of a shunted electrostatic multipole designed with OPERA, a spherical electrostatic bender, and the effects of different shaped apertures in an electrostatic beam line.

Anomalies free E-infinity from von Neumann's continuous geometry

International Nuclear Information System (INIS)

El Naschie, M.S.

2008-01-01

Von Neumann's continuous geometry has been considerably developed by Connes and is characterized by two fundamental concepts. First it is formulated without any direct reference to points and second it possesses a dimensional function. The present work explores the relevance of these two points to string theory as well as E-infinity theory. In particular we show that point-lessness and dimensional function implies fractality. In turn fractality leads to the concept of average or fuzzy symmetry and the elimination of gauge anomalies

From zero to infinity what makes numbers interesting

CERN Document Server

Reid, Constance

2006-01-01

From Zero to Infinity is a combination of number lore, number history, and sparkling descriptions of the simply stated but exceedingly difficult problems posed by the most ordinary numbers that first appeared in 1955 and has been kept in print continuously ever since. With the fifth edition this classic has been updated to report on advances in number theory over the last 50 years, including the proof of Fermat's Last Theorem. Deceptively simple in style and structure, it is a book to which the reader will return again and again, gaining greater understanding and satisfaction with each reading

W-infinity ward identities and correlation functions in the c = 1 matrix model

International Nuclear Information System (INIS)

Das, S.R.; Dhar, A.; Mandal, G.; Wadia, S.R.

1992-01-01

In this paper, the authors explore consequences of W-infinity symmetry in the fermionic field theory of the c = 1 matrix model. The authors derive exact Ward identities relating correlation functions of the bilocal operator. These identities can be expressed as equations satisfied by the effective action of a three-dimensional theory and contain non-perturbative information about the model. The authors use thee identities to calculate the two-point function of the bilocal operator in the double scaling limit. The authors extract the operator whose two-point correlator has a single pole at an (imaginary) integer value of the energy. The authors then rewrite the W-infinity charges in terms of operators in the matrix model and use this to derive constraints satisfied by the partition function of the matrix model with a general time dependent potential

Stability of geodesic imcompleteness for Robertson-Walker space-times

International Nuclear Information System (INIS)

Beem, J.K.

1981-01-01

Let (M,g) be a Lorentzian warped product space-time M = (a, b) X H,g = -dt 2 x fh, where -infinity -infinity and (H,h) is homogeneous, then the past incompleteness of every timelike geodesic of (M,g) is stable under small C 0 perturbations in the space Lor(M) of Lorentzian metrics for M. Also it is shown that if (H,h) is isotropic and (M,g) contains a past-inextendible, past-incomplete null geodesic, then the past incompleteness of all null geodesics is stable under small C 1 perturbations in Lor(M). Given either the isotropy or homogeneity of the Riemannian factor, the background space-time (M,g) is globally hyperbolic. The results of this paper, in particular, answer a question raised by D. Lerner for big bang Robertson-Walker cosmological models affirmatively. (author)

Calculation of K{sub {infinity}} for homogeneous {sup 235}U metal mixtures: Will the real K{sub {infinity}} please stand up?

Energy Technology Data Exchange (ETDEWEB)

Jordan, W.C.; Petrie, L.M.; Wright, R.Q.; Parks, C.V. [Oak Ridge National Lab., TN (United States)

1997-06-01

This paper very briefly analyzes a journal article about calculating k{sub {infinity}} for metals mixed with uranium 235, and compares the article results with other calculation methods. The article suggested that continuous energy cross sections gave more accurate results than groupwise cross sections. The mixtures described in the article were dry, fast systems with several unusual characteristics; however, the majority of multigroup libraries used for analysis were developed for well moderated thermal systems. The results of calculations performed using several different codes and cross sections for three uranium/metal mixtures are presented in this paper. 1 tab.

Twistor theory and the energy-momentum and angular momentum of the gravitational field at spatial infinity

International Nuclear Information System (INIS)

Shaw, W.T.

1983-01-01

Penrose's 'quasi-local mass and angular momentum' is investigated for 2-surfaces near spatial infinity in both linearized theory on Minkowski space and full general relativity. It is shown that for space-times that are radially smooth of order one in the sense of Beig and Schmidt with asymptotically electric Weyl curvature, there exists a global concept of a twistor space at spatial infinity. Global conservation laws for the energy-momentum and angular momentum are obtained, and the ten conserved quantities are shown to be invariant under asymptotic coordinate transformations. The relation to other definitions is discussed briefly. (author)

Properties of three-body decay functions derived with time-like jet calculus beyond leading order

International Nuclear Information System (INIS)

Sugiura, Tetsuya

2002-01-01

Three-body decay functions in time-like parton branching are calculated using the jet calculus to the next-to-leading logarithmic (NLL) order in perturbative quantum chromodynamics (QCD). The phase space contributions from each of the ladder diagrams and interference diagrams are presented. We correct part of the results for the three-body decay functions calculated previously by two groups. Employing our new results, the properties of the three-body decay functions in the regions of soft partons are examined numerically. Furthermore, we examine the contribution of the three-body decay functions modified by the restriction resulting from the kinematical boundary of the phase space for two-body decay in the parton shower model. This restriction leads to some problems for the parton shower model. For this reason, we propose a new restriction introduced by the kinematical boundary of the phase space for two-body decay. (author)

On the (1 + 3) threading of spacetime with respect to an arbitrary timelike vector field

Energy Technology Data Exchange (ETDEWEB)

Bejancu, Aurel [Kuwait University, Department of Mathematics, P.O.Box 5969, Safat (Kuwait); Calin, Constantin [Technical University ' ' Gh.Asachi' ' , Department of Mathematics, Iasi (Romania)

2015-04-15

We develop a newapproach on the (1 + 3) threading of spacetime (M, g) with respect to a congruence of curves defined by an arbitrary timelike vector field. The study is based on spatial tensor fields and on theRiemannian spatial connection ∇*, which behave as 3D geometric objects. We obtain new formulas for local components of the Ricci tensor field of (M, g) with respect to the threading frame field, in terms of the Ricci tensor field of ∇* and of kinematic quantities. Also, new expressions for time covariant derivatives of kinematic quantities are stated. In particular, a new form of Raychaudhuri's equation enables us to prove Lemma 6.3, which completes a well-known lemma used in the proof of the Penrose-Hawking singularity theorems. Finally, we apply the new (1 + 3) formalism to the study of the dynamics of a Kerr-Newman black hole. (orig.)

Meso-structures of dynamical chaos and E-infinity theory

International Nuclear Information System (INIS)

Mukhamedov, A.M.

2009-01-01

A novel proposal is made to develop a unified theory of dynamical chaos using an idea of extra-coordinates. It is supposed that chaos is capable to translate influences from quantum level of description to the classical macroscopic one and vise versa. The notion of macroscopically prepared microstates is proposed to determine a special case of extra-coordinates induced by cooperative effects at quantum resolution of dynamical events. Meso-structures mediating quantum and classical appearances of chaotic motion are studied in the light of E-infinity theory.

Infinity subtraction in a quantum field theory of charges and monopoles

International Nuclear Information System (INIS)

Panagiotakopoulos, C.

1982-03-01

Subtraction of ultraviolet infinities in Zwanziger's local quantum field theory of charges and monopoles is described. It involves an infinite number of graphs. The whole programme rests on the assumption that the infinite summations involved do not give rise to pathological situations and the Ward identities are satisfied even after the string cancellations. The resulting finite theory is Lorentz invariant. (author)

Calculus Limits Involving Infinity: The Role of Students' Informal Dynamic Reasoning

Science.gov (United States)

Jones, Steven R.

2015-01-01

Few studies on calculus limits have centred their focus on student understanding of limits at infinity or infinite limits that involve continuous functions (as opposed to discrete sequences). This study examines student understanding of these types of limits using both pure mathematics and applied-science functions and formulas. Seven calculus…

Beltrami parametrization and gauging of Virasoro and w-infinity algebras

International Nuclear Information System (INIS)

Tatar, L.

1992-07-01

The gauging of the Virasoro and w-infinity algebras are discussed from the point of view of BRST symmetry. Both algebras are realised as ''Russian formulas'' for the curvatures built from the generators of the Lie algebras and the corresponding gauge fields. The generalized curvatures are used to determine the gauge invariant Lagrangians as well as the anomaly structures of the conformal two dimensional theory and the w-gravity. (author). 21 refs

Extraction of Generalized Parton Distributions from combined Deeply Virtual Compton Scattering and Timelike Compton scattering fits

Science.gov (United States)

Boer, Marie

2017-09-01

Generalized Parton Distributions (GPDs) contain the correlation between the parton's longitudinal momentum and their transverse distribution. They are accessed through hard exclusive processes, such as Deeply Virtual Compton Scattering (DVCS). DVCS has already been measured in several experiments and several models allow for extracting GPDs from these measurements. Timelike Compton Scattering (TCS) is, at leading order, the time-reversal equivalent process to DVCS and accesses GPDs at the same kinematics. Comparing GPDs extracted from DVCS and TCS is a unique way for proving GPD universality. Combining fits from the two processes will also allow for better constraining the GPDs. We will present our method for extracting GPDs from DVCS and TCS pseudo-data. We will compare fit results from the two processes in similar conditions and present what can be expected in term of contraints on GPDs from combined fits.

Review of The Joy of x: A Guided Tour of Math, from One to Infinity by Steven Strogatz

OpenAIRE

Michael T. Catalano

2014-01-01

Strogatz, Steven. The Joy of x: A Guided Tour of Math, from One to Infinity, (New York, NY, Houghton Mifflin Harcourt, 2012). 316 pp. ISBN 978-0-547-51765-0 The Joy of x: A Guided Tour of Math, from One to Infinity, by Steven Strogatz, is an engaging and example-filled argument for mathematics as a valuable and enjoyable activity. The thirty chapters are divided into six parts, entitled Numbers, Relationships, Shapes, Change, Data, and Frontiers. The discussion ranges from intuitive expl...

On a connection between Stieltjes continued fraction, KAM theory and E-infinity theory

International Nuclear Information System (INIS)

Marek-Crnjac, L.

2004-01-01

In the present work we establish a connection between El Naschie's E-infinity theory and Stieltjes solution of the problem on the distribution of mass along a line and KAM theory following Gantmacher and Krein mechanical interpretation of Stieltjes' classical research on the subject

Wise Guys: "The Man Who Knew Infinity" and Other Movies about Uppity Geniuses

Science.gov (United States)

Beck, Bernard

2017-01-01

Conventional expectations about subcultural groups can be undermined by unusual performances of some individual members. Several recent movies have concerned people of exceptional ability who unexpectedly excelled at prestigious centers of learning. "The Man Who Knew Infinity," "The Imitation Game," and "The Theory of…

H infinity controller design to a rigid-flexible satellite with two vibration modes

International Nuclear Information System (INIS)

De Souza, A G; De Souza, L C G

2015-01-01

The satellite attitude control system (ACS) design becomes more complex when the satellite structure has components like, flexible solar panels, antennas and mechanical manipulators. These flexible structures can interact with the satellite rigid parts during translational and/or rotational manoeuvre damaging the ACS pointing accuracy. Although, a well-designed controller can suppress such disturbances quickly, the controller error pointing may be limited by the minimum time necessary to suppress such disturbances thus affecting the satellite attitude acquisition. This paper deals with the rigid-flexible satellite ACS design using the H infinity method. The rigid-flexible satellite is represented by a beam connected to a central rigid hub at one end and free at the other one. The equations of motions are obtained considering small flexible deformations and the Euler-Bernoulli hypothesis. The results of the simulations have shown that the H-infinity controller was able to control the rigid motion and suppress the vibrations. (paper)

Fractional order differentiation and robust control design crone, h-infinity and motion control

CERN Document Server

Sabatier, Jocelyn; Melchior, Pierre; Oustaloup, Alain

2015-01-01

This monograph collates the past decade’s work on fractional models and fractional systems in the fields of analysis, robust control and path tracking. Themes such as PID control, robust path tracking design and motion control methodologies involving fractional differentiation are amongst those explored. It juxtaposes recent theoretical results at the forefront in the field, and applications that can be used as exercises that will help the reader to assimilate the proposed methodologies. The first part of the book deals with fractional derivative and fractional model definitions, as well as recent results for stability analysis, fractional model physical interpretation, controllability, and H-infinity norm computation. It also presents a critical point of view on model pseudo-state and “real state”, tackling the problem of fractional model initialization. Readers will find coverage of PID, Fractional PID and robust control in the second part of the book, which rounds off with an extension of H-infinity ...

Ricci time in the Lemaître-Tolman model and the block universe

Science.gov (United States)

Elmahalawy, Yasser; Hellaby, Charles; Ellis, George F. R.

2015-10-01

It is common to think of our universe according to the "block universe" concept, which says that spacetime consists of many "stacked" three-surfaces, labelled by some kind of proper time, . Standard ideas do not distinguish past and future, but Ellis' "evolving block universe" tries to make a fundamental distinction. One proposal for this proper time is the proper time measured along the timelike Ricci eigenlines, starting from the big bang. This work investigates the shape of the "Ricci time" surfaces relative to the the null surfaces. We use the Lemaître-Tolman metric as our inhomogeneous spacetime model, and we find the necessary and sufficient conditions for these constant surfaces, , to be spacelike or timelike. Furthermore, we look at the effect of strong gravity domains by determining the location of timelike S regions relative to apparent horizons. We find that constant Ricci time surfaces are always spacelike near the big bang, while at late times (near the crunch or the extreme far future), they are only timelike under special circumstances. At intermediate times, timelike S regions are common unless the variation of the bang time is restricted. The regions where these surfaces become timelike are often adjacent to apparent horizons, but always outside them, and in particular timelike S regions do not occur inside the horizons of black-hole-like models.

A comparative study of Kalman filter and Linear Matrix Inequality based H infinity filter for SPND delay compensation

International Nuclear Information System (INIS)

Tamboli, P.K.; Duttagupta, Siddhartha P.; Roy, Kallol

2016-01-01

Highlights: • Derivation for delay compensation algorithm using recursive Kalman filter. • Derivation for delay compensation algorithm using Linear Matrix Inequality based H infinity filter. • Process modeling suitable for delay compensation. • Dynamic tuning of the delay compensation algorithm for both Kalman and H infinity filter. • Simulations and trade-off curve for Kalman and H infinity filter. - Abstract: This paper deals with delay compensation of vanadium Self Powered Neutron Detectors (SPNDs) using Linear Matrix Inequality (LMI) based H-infinity filtering method and compares the results with Kalman filtering method. The entire study is established upon the framework of neutron flux estimation in large core Pressurized Heavy Water Reactor (PHWR) in which delayed SPNDs such as vanadium SPNDs are used as in-core flux monitoring detectors. The use of vanadium SPNDs are limited to 3-D flux mapping despite of providing better Signal to Noise Ratio as compared to other prompt SPNDs, due to their small prompt component in the signal. The use of an appropriate delay compensation technique has been always considered to be an effective strategy to build a prompt and accurate estimate of the neutron flux. We also indicate the noise-response trade-off curve for both the techniques. Since all the delay compensation algorithms always suffer from noise amplification, we propose an efficient adaptive parameter tuning technique for improving performance of the filtering algorithm against noise in the measurement.

Hs solutions for nonlinear Schrodinger equations with potentials superquadratic at infinity

International Nuclear Information System (INIS)

Zhang Guoping; Yajima, Kenji; Liu Fengshan

2006-01-01

In this Letter we study the initial value problem for the nonlinear Schrodinger equation with the potential V superquadratic at infinity. With the local smoothing property and Strichartz inequality obtained by the authors, we prove the existence and the uniqueness of the solution for H s -valued initial data and fractional s by combining the L 2 boundedness theory of pseudo differential operators and the fractional derivatives estimate

Future directions in international financial integration research - A crowdsourced perspective

OpenAIRE

Lucey, B.M.; Vigne, S.A.; Ballester, L.; Barbopoulos, L.; Brzeszczynski, J.; Carchano, O.; Dimic, N.; Fernandez, V.; Gogolin, F.; González-Urteaga, A.; Goodell, J.W.; Helbing, P.; Ichev, R.; Kearney, F.; Laing, E.

2018-01-01

This paper is the result of a crowdsourced effort to surface perspectives on the present and future direction of international finance. The authors are researchers in financial economics who attended the INFINITI 2017 conference in the University of Valencia in June 2017 and who participated in the crowdsourcing via the Overleaf platform. This paper highlights the actual state of scientific knowledge in a multitude of fields in finance and proposes different directions for future research.

Effect of bottle height and aspiration rate on postocclusion surge in Infiniti and Millennium peristaltic phacoemulsification machines.

Science.gov (United States)

Ward, Matthew S; Georgescu, Dan; Olson, Randall J

2008-08-01

To assess how flow and bottle height affect postocclusion surge in the Infiniti (Alcon, Inc.) and Millennium (Bausch & Lomb) peristaltic machines. John A. Moran Eye Center Clinical Laboratories, University of Utah, Salt Lake City, Utah. Postocclusion anterior chamber depth changes were measured in human eye-bank eyes using A-scan. Surge was simulated by clamping the aspiration tubing and releasing it at maximum vacuum. In both machines, surge was measured (1) with aspiration held constant at 12 mL/min and bottle heights at 60, 120, and 180 cm and (2) with bottle height held constant at 60 cm and aspiration rates at 12, 24, and 36 mL/min. Surge decreased approximately 40% with each 60 cm increase in bottle height in the Infiniti. It was constant at all bottle heights in the Millennium. At 12 and 24 mL/min aspiration rates, surge in the Millennium was less than half that in the Infiniti (PInfiniti system and was relatively constant with increasing bottle height in the Millennium system. The Millennium may offer a more stable phacoemulsification platform with respect to surge at a higher aspiration rate.

Review of The Joy of x: A Guided Tour of Math, from One to Infinity by Steven Strogatz

Directory of Open Access Journals (Sweden)

Michael T. Catalano

2014-07-01

Full Text Available Strogatz, Steven. The Joy of x: A Guided Tour of Math, from One to Infinity, (New York, NY, Houghton Mifflin Harcourt, 2012. 316 pp. ISBN 978-0-547-51765-0 The Joy of x: A Guided Tour of Math, from One to Infinity, by Steven Strogatz, is an engaging and example-filled argument for mathematics as a valuable and enjoyable activity. The thirty chapters are divided into six parts, entitled Numbers, Relationships, Shapes, Change, Data, and Frontiers. The discussion ranges from intuitive explanations of basic concepts such as place value, the four arithmetic operations, percentage increase and decrease, and solving equations, to “higher” levels of mathematics such as calculus, probability and statistics, group theory, and the nature of infinity. As in John Allen Paulos’ work, Beyond Numeracy, the chapters are short and punchy, and they can be read independently. While the book is not specifically devoted to numeracy, several chapters, especially those in Part Five on Data, address ideas and examples relevant to quantitative literacy.

Comparison of H-infinity control and generalized predictive control for a laser scanner system

DEFF Research Database (Denmark)

Ordys, A.W.; Stoustrup, Jakob; Smillie, I.

2000-01-01

This paper describes tests performed on a laser scanner system to assess the feasibility of H-infinity control and generalized predictive control design techniques in achieving a required performance in a trajectory folowing problem. The two methods are compared with respect to achieved scan times...

Study of the pion electromagnetic form factor in the timelike region, from the production threshold to 900 MeV in the center of mass

International Nuclear Information System (INIS)

Quenzer, A.

1977-01-01

The pion form factor is measured in the reaction e + e - →π + π - for center of mass energies in the range 480-900 MeV. The results are first analysed in terms of the conventional Vector Meson Dominance formalism, and then taking into account the ωπ inelastic channel. The results of this later formalisms is a pion form factor (F) which fits quite well all the existing data on F both in the timelike and spacelike regions, and a pion mean square radius [fr

A method of inferring k-infinity from reaction rate measurements in thermal reactor systems

International Nuclear Information System (INIS)

Newmarch, D.A.

1967-05-01

A scheme is described for inferring a value of k-infinity from reaction rate measurements. The method is devised with the METHUSELAH group structure in mind and was developed for the analysis of S.G.H.W. reactor experiments; the underlying principles, however, are general. (author)

Angular momentum in general relativity. 1. Definition and asymptotic behaviour. [axisymmetric space-times, infinity, conservation law, spin coefficient formalism

Energy Technology Data Exchange (ETDEWEB)

Prior, C R [Cambridge Univ. (UK). Dept. of Applied Mathematics and Theoretical Physics

1977-06-27

Angular momentum in axisymmetric space-times is investigated. The conclusions lead to a general definition suitable for all asymptotically-flat spaces which is valid both at infinity and on the event horizon of a black hole. This first paper restricts attention to considerations at infinity. Working in terms of the spin coefficient formalism, the field equations are solved asymptotically at large distances and the definition is evaluated. A conservation law is derived and finally the effect on the angular momentum of a supertranslation of the coordinates is discussed.

Collisions of massive particles, timelike thin shells and formation of black holes in three dimensions

International Nuclear Information System (INIS)

Lindgren, Jonathan

2016-01-01

We study collisions of massive pointlike particles in three dimensional anti-de Sitter space, generalizing the work on massless particles in http://dx.doi.org/10.1088/0264-9381/33/14/145009. We show how to construct exact solutions corresponding to the formation of either a black hole or a conical singularity from the collision of an arbitrary number of massive particles that fall in radially and collide at the origin of AdS. No restrictions on the masses or the angular and radial positions from where the particles are released, are imposed. We also consider the limit of an infinite number of particles, obtaining novel timelike thin shell spacetimes. These thin shells have an arbitrary mass distribution as well as a non-trivial embedding where the radial location of the shell depends on the angular coordinate, and we analyze these shells using the junction formalism of general relativity. We also consider the massless limit and find consistency with earlier results, as well as comment on the stress-energy tensor modes of the dual CFT.

Collisions of massive particles, timelike thin shells and formation of black holes in three dimensions

Energy Technology Data Exchange (ETDEWEB)

Lindgren, Jonathan [Theoretische Natuurkunde, Vrije Universiteit Brussel, and the International Solvay Institutes,Pleinlaan 2, B-1050 Brussels (Belgium); Physique Théorique et Mathématique, Université Libre de Bruxelles,Campus Plaine C.P. 231, B-1050 Bruxelles (Belgium)

2016-12-13

We study collisions of massive pointlike particles in three dimensional anti-de Sitter space, generalizing the work on massless particles in http://dx.doi.org/10.1088/0264-9381/33/14/145009. We show how to construct exact solutions corresponding to the formation of either a black hole or a conical singularity from the collision of an arbitrary number of massive particles that fall in radially and collide at the origin of AdS. No restrictions on the masses or the angular and radial positions from where the particles are released, are imposed. We also consider the limit of an infinite number of particles, obtaining novel timelike thin shell spacetimes. These thin shells have an arbitrary mass distribution as well as a non-trivial embedding where the radial location of the shell depends on the angular coordinate, and we analyze these shells using the junction formalism of general relativity. We also consider the massless limit and find consistency with earlier results, as well as comment on the stress-energy tensor modes of the dual CFT.

Characteristic extraction in numerical relativity: binary black hole merger waveforms at null infinity

Energy Technology Data Exchange (ETDEWEB)

Reisswig, C; Pollney, D [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, 14476 Golm (Germany); Bishop, N T [Department of Mathematics, Rhodes University, Grahamstown 6140 (South Africa); Szilagyi, B [Theoretical Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)

2010-04-07

The accurate modeling of gravitational radiation is a key issue for gravitational wave astronomy. As simulation codes reach higher accuracy, systematic errors inherent in current numerical relativity wave extraction methods become evident, and may lead to a wrong astrophysical interpretation of the data. In this paper, we give a detailed description of the Cauchy-characteristic extraction technique applied to binary black hole inspiral and merger evolutions to obtain gravitational waveforms that are defined unambiguously, that is, at future null infinity. By this method, we remove finite-radius approximations and the need to extrapolate data from the near zone. Further, we demonstrate that the method is free of gauge effects and thus is affected only by numerical error. Various consistency checks reveal that energy and angular momentum are conserved to high precision and agree very well with extrapolated data. In addition, we revisit the computation of the gravitational recoil and find that finite-radius extrapolation very well approximates the result at J{sup +}. However, the (non-convergent) systematic differences in the extrapolated data are of the same order of magnitude as the (convergent) discretization error of the Cauchy evolution, thus highlighting the need for correct wave extraction.

Infinity: An In-Silico Tool for Genome-Wide Prediction of Specific DNA Matrices in miRNA Genomic Loci.

Science.gov (United States)

Falcone, Emmanuela; Grandoni, Luca; Garibaldi, Francesca; Manni, Isabella; Filligoi, Giancarlo; Piaggio, Giulia; Gurtner, Aymone

2016-01-01

miRNAs are potent regulators of gene expression and modulate multiple cellular processes in physiology and pathology. Deregulation of miRNAs expression has been found in various cancer types, thus, miRNAs may be potential targets for cancer therapy. However, the mechanisms through which miRNAs are regulated in cancer remain unclear. Therefore, the identification of transcriptional factor-miRNA crosstalk is one of the most update aspects of the study of miRNAs regulation. In the present study we describe the development of a fast and user-friendly software, named infinity, able to find the presence of DNA matrices, such as binding sequences for transcriptional factors, on ~65kb (kilobase) of 939 human miRNA genomic sequences, simultaneously. Of note, the power of this software has been validated in vivo by performing chromatin immunoprecipitation assays on a subset of new in silico identified target sequences (CCAAT) for the transcription factor NF-Y on colon cancer deregulated miRNA loci. Moreover, for the first time, we have demonstrated that NF-Y, through its CCAAT binding activity, regulates the expression of miRNA-181a, -181b, -21, -17, -130b, -301b in colon cancer cells. The infinity software that we have developed is a powerful tool to underscore new TF/miRNA regulatory networks. Infinity was implemented in pure Java using Eclipse framework, and runs on Linux and MS Windows machine, with MySQL database. The software is freely available on the web at https://github.com/bio-devel/infinity. The website is implemented in JavaScript, PHP and HTML with all major browsers supported.

Infinity: An In-Silico Tool for Genome-Wide Prediction of Specific DNA Matrices in miRNA Genomic Loci.

Directory of Open Access Journals (Sweden)

Emmanuela Falcone

Full Text Available miRNAs are potent regulators of gene expression and modulate multiple cellular processes in physiology and pathology. Deregulation of miRNAs expression has been found in various cancer types, thus, miRNAs may be potential targets for cancer therapy. However, the mechanisms through which miRNAs are regulated in cancer remain unclear. Therefore, the identification of transcriptional factor-miRNA crosstalk is one of the most update aspects of the study of miRNAs regulation.In the present study we describe the development of a fast and user-friendly software, named infinity, able to find the presence of DNA matrices, such as binding sequences for transcriptional factors, on ~65kb (kilobase of 939 human miRNA genomic sequences, simultaneously. Of note, the power of this software has been validated in vivo by performing chromatin immunoprecipitation assays on a subset of new in silico identified target sequences (CCAAT for the transcription factor NF-Y on colon cancer deregulated miRNA loci. Moreover, for the first time, we have demonstrated that NF-Y, through its CCAAT binding activity, regulates the expression of miRNA-181a, -181b, -21, -17, -130b, -301b in colon cancer cells.The infinity software that we have developed is a powerful tool to underscore new TF/miRNA regulatory networks.Infinity was implemented in pure Java using Eclipse framework, and runs on Linux and MS Windows machine, with MySQL database. The software is freely available on the web at https://github.com/bio-devel/infinity. The website is implemented in JavaScript, PHP and HTML with all major browsers supported.

Toeplitz quantization of Kaehler manifolds and gl(N), N [yields] [infinity] limits

Energy Technology Data Exchange (ETDEWEB)

Bordemann, M. (Dept. of Physics, Univ. of Freiburg (Germany)); Meinrenken, E. (Dept. of Mathematics, M.I.T., Cambridge, MA (United States)); Schlichenmaier, M. (Dept. of Mathematics and Computer Science, Univ. of Mannheim (Germany))

1994-10-01

For general compact Kaehler manifolds it is shown that both Toeplitz quantization and geometric quantization lead to a well-defined (by operator norm estimates) classical limit. This generalizes earlier results of the authors and Klimek and Lesniewski obtained for the torus and higher genus Riemann surfaces, respectively. We thereby arrive at an approximation of the Poisson algebra by a sequence of finite-dimensional matrix algebras gl(N), N [yields] [infinity]. (orig.)

Supergravity on an Atiyah-Hitchin base

International Nuclear Information System (INIS)

Stotyn, Sean; Mann, R.B.

2008-01-01

We construct solutions to five dimensional minimal supergravity using an Atiyah-Hitchin base space. In examining the structure of solutions we show that they generically contain a singularity either on the Atiyah-Hitchin bolt or at larger radius where there is a singular solitonic boundary. However for most points in parameter space the solution exhibits a velocity of light surface (analogous to what appears in a Goedel space-time) that shields the singularity. For these solutions, all closed time-like curves are causally disconnected from the rest of the space-time in that they exist within the velocity of light surface, which null geodesics are unable to cross. The singularities in these solutions are thus found to be hidden behind the velocity of light surface and so are not naked despite the lack of an event horizon. Outside of this surface the space-time is geodesically complete, asymptotically flat and can be arranged so as not to contain closed time-like curves at infinity. The rest of parameter space simply yields solutions with naked singularities.

A New Upper Bound on the Infinity Norm of the Inverse of Nekrasov Matrices

Directory of Open Access Journals (Sweden)

Lei Gao

2014-01-01

Full Text Available A new upper bound which involves a parameter for the infinity norm of the inverse of Nekrasov matrices is given. And we determine the optimal value of the parameter such that the bound improves the results of Kolotilina, 2013. Numerical examples are given to illustrate the corresponding results.

A positive semi-definite action in a Kaluza-Klein theory with compactification onto time-like extra dimensions

International Nuclear Information System (INIS)

Pollock, M.D.

1986-01-01

We consider the (4+N)-dimensional theory whose Lagrangian function is Lsub(4+N)=√-g-circumflex α R-circumflex 2 , where R-circumflex is the Ricci scalar and α is a positive constant. The metric is g-circumflexsub(AB)= diag(gsub(ab), phi -1 g-barsub(mn)). Dimensional reduction leads to an effective four-dimensional Lagrangian of induced-gravity type. The positive semi-definiteness of L avoids the difficulties, pointed out recently by Horowitz and by Rubakov, which can arise in quantum cosmology when the (Euclidean) action becomes negative. The compactification is onto a time-like internal space g-barsub(mn), as suggested by Aref'eva and Volovich, giving a four-dimensional de Sitter space-time with phi=constant, which however is classically unstable on a time scale approx. H -1 . Decrease of the radius phisup(-1/2) of the internal space is ultimately halted by quantum effects, via some V(phi), and L 4 then includes the usual Hilbert term and a cosmological constant. (author)

Lower bounds on the total cross section and the slope parameter for some measurable sequences of s→infinity

International Nuclear Information System (INIS)

Uchiyama, T.

1978-01-01

The lower bounds on the total cross section and the slope parameter are obtained on the basis of the analyticity and polynomial upper boundedness of the scattering amplitude and the unitarity of the S matrix: sigma/sub tot/> or =Cs -6 (logs) -2 , B> or =Cs -5 (logs) -4 for some measurable sequences of s→infinity. These bounds hold for any t in 0 2 /sub π/It is unnecessary in order to obtain our bounds that the scattering amplitude has the crossing even property. If we assume this property, we can suppress the logarithmic factors of our bounds. Also we obtain our lower bounds for any sequence of s→infinity, if we take the average scattering amplitude

On the behavior at infinity of the separatrix of a static model

International Nuclear Information System (INIS)

Zhuravlev, V.I.; Meshcheryakov, V.A.

2010-01-01

A method of studying static model equations (scattering of a relativistic particle on the fixed center) in projective spaces is suggested. Its basis is the construction of a set of affine coordinates of the problem at a zero total energy. The method is exemplified by the three-row matrix of crossing symmetry. Each element of the set leads to the solution with the same Riemann surface on which the behavior of the separatrix at infinity is considered

Robust Estimation of HDR in fMRI using H-infinity Filters

DEFF Research Database (Denmark)

Puthusserypady, Sadasivan; Jue, R.; Ratnarajah, T.

2010-01-01

Estimation and detection of the hemodynamic response (HDR) are of great importance in functional MRI (fMRI) data analysis. In this paper, we propose the use of three H-infinity adaptive filters (finite memory, exponentially weighted, and timevarying) for accurate estimation and detection of the HDR......-1487]. Performances of the proposed techniques are compared to the conventional t-test method as well as the well-known LMSs and recursive least squares algorithms. Extensive numerical simulations show that the proposed methods result in better HDR estimations and activation detections....

Timelike and null focusing singularities in spherical symmetry: A solution to the cosmological horizon problem and a challenge to the cosmic censorship hypothesis

International Nuclear Information System (INIS)

Celerier, Marie-Noeelle; Szekeres, Peter

2002-01-01

Extending the study of spherically symmetric metrics satisfying the dominant energy condition and exhibiting singularities of power-law type initiated by Szekeres and Iyer, we identify two classes of peculiar interest: focusing timelike singularity solutions with the stress-energy tensor of a radiative perfect fluid (equation of state: p=(1/3)ρ) and a set of null singularity classes verifying identical properties. We consider two important applications of these results: to cosmology, as regards the possibility of solving the horizon problem with no need to resort to any inflationary scenario, and to the strong cosmic censorship hypothesis to which we propose a class of physically consistent counterexamples

Measurement of M{sup 3} and k{sub {infinity}} for heavy water natural uranium assembly

Energy Technology Data Exchange (ETDEWEB)

Popovic, D; Raisic, N; Markovic, H; Takac, S; Zdravkovic, Z; Lolic, B [Boris Kidric Institute of Nuclear Sciences, Vinca, Beograd (Yugoslavia)

1959-03-15

The migration length M and the infinite multiplication factor k{sub {infinity}} of the heavy water-natural uranium bare assembly are determined by measuring the reactivity of the reactor as function of the heavy water level. Since the assembly is non reflected the results obtained are of relatively high accuracy. (author)

Stability and Instability of the Sub-extremal Reissner-Nordström Black Hole Interior for the Einstein-Maxwell-Klein-Gordon Equations in Spherical Symmetry

Science.gov (United States)

Van de Moortel, Maxime

2018-05-01

We show non-linear stability and instability results in spherical symmetry for the interior of a charged black hole—approaching a sub-extremal Reissner-Nordström background fast enough—in presence of a massive and charged scalar field, motivated by the strong cosmic censorship conjecture in that setting: 1. Stability We prove that spherically symmetric characteristic initial data to the Einstein-Maxwell-Klein-Gordon equations approaching a Reissner-Nordström background with a sufficiently decaying polynomial decay rate on the event horizon gives rise to a space-time possessing a Cauchy horizon in a neighbourhood of time-like infinity. Moreover, if the decay is even stronger, we prove that the space-time metric admits a continuous extension to the Cauchy horizon. This generalizes the celebrated stability result of Dafermos for Einstein-Maxwell-real-scalar-field in spherical symmetry. 2. Instability We prove that for the class of space-times considered in the stability part, whose scalar field in addition obeys a polynomial averaged- L 2 (consistent) lower bound on the event horizon, the scalar field obeys an integrated lower bound transversally to the Cauchy horizon. As a consequence we prove that the non-degenerate energy is infinite on any null surface crossing the Cauchy horizon and the curvature of a geodesic vector field blows up at the Cauchy horizon near time-like infinity. This generalizes an instability result due to Luk and Oh for Einstein-Maxwell-real-scalar-field in spherical symmetry. This instability of the black hole interior can also be viewed as a step towards the resolution of the C 2 strong cosmic censorship conjecture for one-ended asymptotically flat initial data.

The busy period of order n in the GI/D/infinity queue

International Nuclear Information System (INIS)

Dvurecenskij, A.

1982-01-01

The problem of determination of the distribution function, integral equation and all moments of the busy period of order n, that is, the period when at least n servers are busy from infinitely many servers of the GI/D/infinity queueing system are investigated. The idle period of order n, i. e., the period between two neighbouring busy periods of order n is also studied. Those problems arise in the blob length determination in track chambers in high energy physics

Electrodynamics with a Future Conformal Horizon

International Nuclear Information System (INIS)

Ibison, Michael

2010-01-01

We investigate the impact of singularities occurring at future times in the Friedmann equations expressed in conformal coordinates to determine the consequences of extending the time coordinate through the singularity for the physics of matter and radiation occupying just one side. Mostly this involves investigation of the relationship between the metric with line element ds 2 a 2 (t)(dt 2 -dx 2 ) and time reversal symmetry within electrodynamics. It turns out compatibility between these two is possible only if there is a singular physical event at the time of the singularity or if the topology is not trivial. In both cases the singularity takes on the appearance of a time-like mirror. We are able to demonstrate a relationship between the broken time symmetry in electrodynamics characterized by retarded radiation and radiation reaction and the absolute conformal time relative to the time of the singularity, i.e. between the Electromagnetic and Cosmological arrows of time. It is determined that the Wheeler-Feynman reasoning but with the future absorber replaced by the Cosmological mirror leads to a conflict with observation unless matter is strongly bound electromagnetically to the environment.

Multivariable H{sub 2} and H{infinity} control for a wind energy conversion system - a comparison

Energy Technology Data Exchange (ETDEWEB)

Rocha, Ronilson; Coutinho, Gilmar Alves; Ferreira, Alexandre Jose; Torga, Flavio Allison [Universidade Federal de Ouro Preto (EM/DECAT/UFOP), MG (Brazil). Escola de Minas. Dept. de Engenharia de Controle e Automacao e de Tecnicas Fundamentais], Emails: rocha@em.ufop.br, gacoutinho@gmail.com, aleengaut@yahoo.com.br, torgautomacao@yahoo.com.br

2010-10-15

The Wind Energy Conversion System (WECS) is a nonlinear system, highly dependent on a stochastic variable characterized by sudden variations, and subjected to cyclical disturbances caused by operational phenomena. Thus, the quality of a WECS controller is measured by its capacity to deal with unmodeled dynamics, stochastic signals, and periodic, as well as non-periodic disturbances. Since the WECS' objectives can be easily specified in terms of maximum allowable gain in the disturbance-to-output transfer functions, H2 and H{infinity} methodologies can be good options for designing a WECS stabilizing controller, combining specifications such as: disturbance attenuation, asymptotic tracking, bandwidth limitation, robust stability, and trade-off between performance and control effort. Designs for WECS multivariable feedback controllers based on H2 and H{infinity} methodologies are presented in this paper. The performances of both controllers are computationally simulated, analyzed and compared in order to identify the advantages and drawbacks of each controller design. (author)

Volvo and Infiniti drivers' experiences with select crash avoidance technologies.

Science.gov (United States)

Braitman, Keli A; McCartt, Anne T; Zuby, David S; Singer, Jeremiah

2010-06-01

Vehicle-based crash avoidance systems can potentially reduce crashes, but success depends on driver acceptance and understanding. This study gauged driver use, experience, and acceptance among early adopters of select technologies. Telephone interviews were conducted in early 2009 with 380 owners of Volvo vehicles equipped with forward collision warning with autobrake, lane departure warning, side-view assist, and/or active bi-xenon headlights and 485 owners of Infiniti vehicles with lane departure warning/prevention. Most owners kept systems turned on most of the time, especially forward collision warning with autobrake and side-view assist. The exception was lane departure prevention; many owners were unaware they had it, and the system must be activated each time the vehicle is started. Most owners reported being safer with the technologies and would want them again on their next vehicles. Perceived false or unnecessary warnings were fairly common, particularly with side-view assist. Some systems were annoying, especially lane departure warning. Many owners reported safer driving behaviors such as greater use of turn signals (lane departure warning), increased following distance (forward collision warning), and checking side mirrors more frequently (side-view assist), but some reported driving faster at night (active headlights). Despite some unnecessary or annoying warnings, most Volvo and Infiniti owners use crash avoidance systems most of the time. Among early adopters, the first requirement of effective warning systems (that owners use the technology) seems largely met. Systems requiring activation by drivers for each trip are used less often. Owner experience with the latest technologies from other automobile manufacturers should be studied, as well as for vehicles on which technologies are standard (versus optional) equipment. The effectiveness of technologies in preventing and mitigating crashes and injuries, and user acceptance of interfaces, should be

From pointillism to E-infinity electromagnetism

International Nuclear Information System (INIS)

El Naschie, M.S.

2007-01-01

Pretty much like in a pointillism masterpiece of say Georges Seurat or Paul Signac, quantum space-time, which is in reality a collection of transfinite discrete set of points, appears when observed at a distance to be a nowhere disjoined continuum. This geometry which is best described by its Hausdorff dimension leads us ultimately to a radical change of some of our most basic mathematical assumptions with regard to the corresponding symmetry groups. Thus instead of being restricted to an integer value of the order of these symmetry groups, it seems natural to extend this order to the realm of irrational transfinite numbers. This step is not as strange as it may seem when we consider the role played by the factorial function n! in elementary group theory and its extension for non-integer value of n using the well-known Gauss' Gamma function. Proceeding in this way, we find that the space-time of E-infinity theory constitutes a transfinite pointillism setting in which all fundamental interactions could be accounted for via the corresponding transfinite order of its symmetry groups and finally we find a conservation equation from which the exact inverse fine structure constant α-bar o may be accurately determined

From pointillism to E-infinity electromagnetism

Energy Technology Data Exchange (ETDEWEB)

El Naschie, M S [Department of Astrophysics, Faculty of Science, Cairo University (Egypt); Department of Physics, Alexandria University (Egypt)

2007-12-15

Pretty much like in a pointillism masterpiece of say Georges Seurat or Paul Signac, quantum space-time, which is in reality a collection of transfinite discrete set of points, appears when observed at a distance to be a nowhere disjoined continuum. This geometry which is best described by its Hausdorff dimension leads us ultimately to a radical change of some of our most basic mathematical assumptions with regard to the corresponding symmetry groups. Thus instead of being restricted to an integer value of the order of these symmetry groups, it seems natural to extend this order to the realm of irrational transfinite numbers. This step is not as strange as it may seem when we consider the role played by the factorial function n{exclamation_point} in elementary group theory and its extension for non-integer value of n using the well-known Gauss' Gamma function. Proceeding in this way, we find that the space-time of E-infinity theory constitutes a transfinite pointillism setting in which all fundamental interactions could be accounted for via the corresponding transfinite order of its symmetry groups and finally we find a conservation equation from which the exact inverse fine structure constant {alpha}-bar{sub o} may be accurately determined.

From pointillism to E-infinity electromagnetism

Energy Technology Data Exchange (ETDEWEB)

El Naschie, M.S. [Department of Astrophysics, Faculty of Science, Cairo University (Egypt); Department of Physics, Alexandria University (Egypt)

2007-12-15

Pretty much like in a pointillism masterpiece of say Georges Seurat or Paul Signac, quantum space-time, which is in reality a collection of transfinite discrete set of points, appears when observed at a distance to be a nowhere disjoined continuum. This geometry which is best described by its Hausdorff dimension leads us ultimately to a radical change of some of our most basic mathematical assumptions with regard to the corresponding symmetry groups. Thus instead of being restricted to an integer value of the order of these symmetry groups, it seems natural to extend this order to the realm of irrational transfinite numbers. This step is not as strange as it may seem when we consider the role played by the factorial function n{exclamation_point} in elementary group theory and its extension for non-integer value of n using the well-known Gauss' Gamma function. Proceeding in this way, we find that the space-time of E-infinity theory constitutes a transfinite pointillism setting in which all fundamental interactions could be accounted for via the corresponding transfinite order of its symmetry groups and finally we find a conservation equation from which the exact inverse fine structure constant {alpha}-bar{sub o} may be accurately determined.

Some Historical Issues and Paradoxes Regarding the Concept of Infinity: An APOS Analysis: Part 2

Science.gov (United States)

Dubinsky, Ed; Weller, Kirk; McDonald, Michael A.; Brown, Anne

2005-01-01

This is Part 2 of a two-part study of how APOS theory may be used to provide cognitive explanations of how students and mathematicians might think about the concept of infinity. We discuss infinite processes, describe how the mental mechanisms of interiorization and encapsulation can be used to conceive of an infinite process as a completed…

Precision Measurements of the Proton Electromagnetic Form Factors in the Time-Like Region and Vector Meson Spectroscopy

CERN Multimedia

2002-01-01

The aim of this experiment is to measure with precision the electromagnetic form factors of the proton in the time-like region via the reaction: .ce @*p @A e|+e|- with antiprotons of momenta between 0 and 2 GeV/c. Up to @= 800 MeV/c, a continuous energy scan in @= 2 MeV (@]s) bins will be performed. The form factor !G(E)! and !G(M)! will be determined separately since large statistics can be collected with LEAR antiproton beams, so that angular distributions can be obtained at many momenta.\\\\ \\\\ In addition, e|+e|- pairs produced via the reaction: .ce @*p @A V|0 + neutrals, .ce !@A e|+e|- where the antiprotons are at rest, will be detected allowing the vector meson mass spectrum between @= 1 GeV and @= 1.7 GeV to be obtained with high statistics and in one run. \\\\ \\\\ The proposed apparatus consists of a central detector, surrounded by a gas Cerenkov counter, wire chambers, hodoscopes, and an electromagnetic calorimeter. The central detector consists of several layers of proportional chambers around a liquid-h...

Comparison of cumulative dissipated energy between the Infiniti and Centurion phacoemulsification systems [Corrigendum

OpenAIRE

2015-01-01

Chen M, Anderson E, Hill G, et al. Clin Ophthalmol. 2015;9:1367–1372.  On page 1367, the final sentence of the Introduction which reads:  “The purpose of this study was simply to compare the CDE between the single Centurion and single Infiniti phacoemulsification systems in a larger number of cases to see which one uses less CDE under similar age, sex, and complication rate (P>0.05) among five surgeons in one surgical center.” &a...

Transmitting information of an object behind the obstacle to infinity

Science.gov (United States)

Xu, Bai Bing; Jiang, Wei Xiang; Meng, Ling Ling; Cui, Tie Jun

2015-08-01

We propose an illusion device that transforms a metallic cylinder into a Luneburg lens by using transformation optics. Such a transformed focusing lens guides electromagnetic waves to propagate around the central metallic cylinder smoothly and be focused on one spot, and thus the information of an object behind the obstacle can be transmitted to infinity. In order to realize the required-anisotropic parameters with high permittivity and low permeability, we design embedded split-ring resonators (SRRs) to increase the permittivity of the traditional SRR structures. In experiments, we fabricate and measure the transformed lens, and the tested results agree well with the numerical simulations and theoretical predictions. The proposed transformation lens can mimic some properties of Einstein gravitational lens because their wave propagation behaviors are very similar.

Stabilization of the solution of a two-dimensional system of Navier-Stokes equations in an unbounded domain with several exits to infinity

International Nuclear Information System (INIS)

Khisamutdinova, N A

2003-01-01

The behaviour as t→∞ of the solution of the mixed problem for the system of Navier-Stokes equations with a Dirichlet condition at the boundary is studied in an unbounded two-dimensional domain with several exits to infinity. A class of domains is distinguished in which an estimate characterizing the decay of solutions in terms of the geometry of the domain is proved for exponentially decreasing initial velocities. A similar estimate of the solution of the first mixed problem for the heat equation is sharp in a broad class of domains with several exits to infinity

On the limit of Brans-Dicke theory when omega -> infinity

CERN Document Server

Chauvineau, B

2003-01-01

We discuss the problem of the limit of the Brans-Dicke theory (BDT) in the limit omega -> infinity, when the trace of the stress tensor is not zero. It is shown that a BDT solution, with T not = 0, known in the framework of anisotropic cosmology, fails to converge to the general relativity theory (GRT) corresponding solution. Considering the spherically symmetric field problem, it is shown that the argument leading to the convergence in the static case is lost when the non-static case is considered. These remarks suggest that the non-convergence of BDT to GRT could be the general behaviour, even if T not = 0, except for some (most?) of the highly symmetric solutions, including most of the known ones. The impact on gravitational radiation detection is emphasized.

LA GEOMETRIA NON-ARCHIMEDEA. DALLE PREMESSE AGLI INFINITI MODELLI ATTUALI

Directory of Open Access Journals (Sweden)

R. Mascella

2006-02-01

Full Text Available La geometria non-archimedea sembra essere un’ipotesi astratta e fantasiosa, accettabile nella matematica ma non per la rappresentazione spaziale, perché usa concetti a lungo esplorati nel pensiero scientifico e filosofico e spesso rigettati, quali l’infinito e l’infinitesimo attuali. L’articolo analizza gli aspetti storici, epistemologici, filosofici e matematici legati a questa geometria ed alle sue radici, considerando l’impostazione dell’inventore Giuseppe Veronese, della formalizzazione analitica di Levi-Civita e di altri matematici e filosofici che sul tema hanno fornito risultati e dibattuto, quali Cantor, Hilbert e Hahn, per terminare con gli infiniti modelli che oggi conosciamo. Questa geometria appare sottovalutata, ma si presta ad un ruolo non meno importante di alcune alternative non-euclidee, spesso semplicisticamente considerate come uniche varianti astratte dei modelli euclideo e riemanniano.

Complete spacelike immersions with topology

International Nuclear Information System (INIS)

Harris, S.G.

1988-01-01

A fairly large class of Lorentz manifolds is defined, called WH normal manifolds, which are approximately those for which timelike infinity is a single point. It is shown that, in such a space, an immersed spacelike hypersurface which is complete must, if it is self-intersecting, not achronal or proper, satisfy strong topological conditions; in particular, if the immersion is injective in the fundamental group, then the hypersurface must be closed, embedded and achronal (i.e. a partial Cauchy surface). WH normal spaces include products of any Riemannian manifold with Minkowski 1-space; in such space, a complete immersed spacelike hypersurface must be immersed as a covering space for the Riemannian factor. (author)

Born-Infeld determinantal gravity and the taming of the conical singularity in 3-dimensional spacetime

Energy Technology Data Exchange (ETDEWEB)

Ferraro, Rafael, E-mail: ferraro@iafe.uba.a [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina); Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina); Fiorini, Franco, E-mail: franco@iafe.uba.a [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina)

2010-08-30

In the context of Born-Infeld determinantal gravity formulated in an n-dimensional spacetime with absolute parallelism, we found an exact 3-dimensional vacuum circular symmetric solution without cosmological constant consisting in a rotating spacetime with non-singular behavior. The space behaves at infinity as the conical geometry typical of 3-dimensional General Relativity without cosmological constant. However, the solution has no conical singularity because the space ends at a minimal circle that no freely falling particle can ever reach in a finite proper time. The space is curved, but no divergences happen since the curvature invariants vanish at both asymptotic limits. Remarkably, this very mechanism also forbids the existence of closed timelike curves in such a spacetime.

Born-Infeld determinantal gravity and the taming of the conical singularity in 3-dimensional spacetime

International Nuclear Information System (INIS)

Ferraro, Rafael; Fiorini, Franco

2010-01-01

In the context of Born-Infeld determinantal gravity formulated in an n-dimensional spacetime with absolute parallelism, we found an exact 3-dimensional vacuum circular symmetric solution without cosmological constant consisting in a rotating spacetime with non-singular behavior. The space behaves at infinity as the conical geometry typical of 3-dimensional General Relativity without cosmological constant. However, the solution has no conical singularity because the space ends at a minimal circle that no freely falling particle can ever reach in a finite proper time. The space is curved, but no divergences happen since the curvature invariants vanish at both asymptotic limits. Remarkably, this very mechanism also forbids the existence of closed timelike curves in such a spacetime.

H-Infinity robust controller design for the synchronization of master-slave chaotic systems with disturbance input

Directory of Open Access Journals (Sweden)

Hamid Reza Karimi

2012-01-01

Full Text Available This paper is concerned with the robust control problems for the synchronization of master-slave chaotic systems with disturbance input. By constructing a series of Lyapunov functions, novel H-Infinity robust synchronization controllers are designed, whose control regulation possess the characteristic of simpleness and explicitness. Finally, numerical simulations are provided to demonstrate the effectiveness of the proposed techniques.

New potential for the Leitz Infinity Coordinate Measuring Machine

CERN Document Server

Sanz, Claude; MAINAUD DURAND , Hélène; Schneider, Jurgen; Steffens, Norbert; Morantz , Paul; Shore , Paul

2015-01-01

The following study is realised within the frame of the PACMAN project: a study on Particle Accelerator Components Metrology and Alignment to the Nanometre scale, which is a Marie Curie program supported by the European commission and hosted by CERN (European Organisation for Nuclear Research). The aim of this program is to develop and build a pre-alignment bench on which each component is aligned to the required level in one single step using a stretched wire. During the operation, the centre of the stretched wire is aligned with the magnetic axis of the magnet. Then, the position of the wire is measured to the highest possible accuracy using a 3D Coordinate Measuring Machine (CMM) Leitz PMM-C Infinity from HEXAGON Metrology. The research described in this paper is two-fold: on one hand we apply a strong magnetic field to the head of the CMM and evaluate its influence on the measurement accuracy; on the other hand we measure the position

Fluidics and heat generation of Alcon Infiniti and Legacy, Bausch & Lomb Millennium, and advanced medical optics sovereign phacoemulsification systems.

Science.gov (United States)

Floyd, Michael S; Valentine, Jeremy R; Olson, Randall J

2006-09-01

To study heat generation, vacuum, and flow characteristics of the Alcon Infiniti and Bausch & Lomb Millennium with results compared with the Alcon Legacy and advanced medical optics (AMO) Sovereign machines previously studied. Experimental study. Heat generation with continuous ultrasound was determined with and without a 200-g weight. Flow and vacuum were determined from 12 to 40-ml/min in 2-ml/min steps. The impact of a STAAR Cruise Control was also tested. Millennium created the most heat/20% of power (5.67 +/- 0.51 degrees C unweighted and 6.80 +/- 0.80 degrees C weighted), followed by Sovereign (4.59 +/- 0.70 degrees C unweighted and 5.65 +/- 0.72 degrees C weighted), Infiniti (2.79 +/- 0.62 degrees C unweighted and 3.96 +/- 0.31 degrees C weighted), and Legacy (1.99 +/- 0.49 degrees C unweighted and 4.27 +/- 0.76 degrees C weighted; P Infiniti vs Legacy, both weighted). Flow studies revealed that Millennium Peristaltic was 17% less than indicated (P < .0001 to all other machines), and all other machines were within 3.5% of indicated. Cruise Control decreased flow by 4.1% (P < .0001 for same machine without it). Millennium Venturi had the greatest vacuum (81% more than the least Sovereign; P < .0001), and Cruise Control increased vacuum in a peristaltic machine 35% more than the Venturi system (P < .0001). Percent power is not consistent in regard to heat generation, however, flow was accurate for all machines except Millennium Peristaltic. Restriction with Cruise Control elevates unoccluded vacuum to levels greater than the Venturi system tested.

From here and now to infinity and eternity: a message to new medical doctors(*).

Science.gov (United States)

Lapeña, José Florencio F

2014-01-01

Commencement means both an end and a beginning; the end of the academic year and the beginning of the rest of your life as new physicians. For such a beginning, it is useful to view it in retrospect, from the point of view of the end, by conducting a pre-mortem on your life. Taking the existentialist (ex sistere, to stand forth) stance, each of us can be classified into one of four basic types of person, based on our characteristic space and time (or spatio-temporal) context or horizon. Our space can be limited to the "here" and our time to the "now;" or our space may extend to "infinity" and our time embark on "eternity." In-between these poles, most have space contexts rooted in their home and work "turf" and time involving their "lifetime," while some expand their space to include the "world" and their time to encompass "history." From the "here and now" and "turf and lifetime" contexts, the horizons of "world and history," and "infinity and eternity" are examined, challenging new medical doctors to realize their full potential. The new physician is exhorted not to wait for a post-mortem to define (des finitus, to set limits) his or her life. He or she should stand forth, to live, and give life. The new medical doctor is encouraged to look to the sunrise, draw strength from the sunshine, to be brave, and strong and true.

On the number of observable customers, served during he busy period of GI/GI/infinity queue

International Nuclear Information System (INIS)

Dvurechenskij, A.

1982-01-01

It is proved that the number of observable customers, served during the busy period of the GI/GI infinity queue with infinitely many servers has a geometric distribution. The parameter of this distribution is determined, too. It is shown that the normalized distributions converge to the exponential distribution. As a particular result is obtained that the distribution of the number of nonabsorbing streamers in a streamer blob has a geometric distribution

Hypersonic vehicle model and control law development using H(infinity) and micron synthesis

Science.gov (United States)

Gregory, Irene M.; Chowdhry, Rajiv S.; Mcminn, John D.; Shaughnessy, John D.

1994-01-01

The control system design for a Single Stage To Orbit (SSTO) air breathing vehicle will be central to a successful mission because a precise ascent trajectory will preserve narrow payload margins. The air breathing propulsion system requires the vehicle to fly roughly halfway around the Earth through atmospheric turbulence. The turbulence, the high sensitivity of the propulsion system to inlet flow conditions, the relatively large uncertainty of the parameters characterizing the vehicle, and continuous acceleration make the problem especially challenging. Adequate stability margins must be provided without sacrificing payload mass since payload margins are critical. Therefore, a multivariable control theory capable of explicitly including both uncertainty and performance is needed. The H(infinity) controller in general provides good robustness but can result in conservative solutions for practical problems involving structured uncertainty. Structured singular value mu framework for analysis and synthesis is potentially much less conservative and hence more appropriate for problems with tight margins. An SSTO control system requires: highly accurate tracking of velocity and altitude commands while limiting angle-of-attack oscillations, minimized control power usage, and a stabilized vehicle when atmospheric turbulence and system uncertainty are present. The controller designs using H(infinity) and mu-synthesis procedures were compared. An integrated flight/propulsion dynamic mathematical model of a conical accelerator vehicle was linearized as the vehicle accelerated through Mach 8. Vehicle acceleration through the selected flight condition gives rise to parametric variation that was modeled as a structured uncertainty. The mu-analysis approach was used in the frequency domain to conduct controller analysis and was confirmed by time history plots. Results demonstrate the inherent advantages of the mu framework for this class of problems.

Infinity in Logic and Computation: International Conference, ILC 2007, Cape Town, South Africa, November 3-5, 2007: Revised selected papers

NARCIS (Netherlands)

Archibald, M.; Brattka, V.; Goranko, V.; Löwe, B.

2009-01-01

Edited in collaboration with FoLLI, the Association of Logic, Language and Information, this volume constitutes a selection of papers presented at the Internatonal Conference on Infinity in Logic and Computation, ILC 2007, held in Cape Town, South Africa, in November 2007. The 7 revised papers

Guide for the 2 infinities - the infinitely big and the infinitely small

International Nuclear Information System (INIS)

Armengaud, E.; Arnaud, N.; Aubourg, E.; Bassler, U.; Binetruy, P.; Bouquet, A.; Boutigny, D.; Brun, P.; Chassande-Mottin, E.; Chardin, G.; Coustenis, A.; Descotes-Genon, S.; Dole, H.; Drouart, A.; Elbaz, D.; Ferrando, Ph.; Glicenstein, J.F.; Giraud-Heraud, Y.; Halloin, H.; Kerhoas-Cavata, S.; De Kerret, H.; Klein, E.; Lachieze-Rey, M.; Lagage, P.O.; Langer, M.; Lebrun, F.; Lequeux, J.; Meheut, H.; Moniez, M.; Palanque-Delabrouille, N.; Paul, J.; Piquemal, F.; Polci, F.; Proust, D.; Richard, F.; Robert, J.L.; Rosnet, Ph.; Roudeau, P.; Royole-Degieux, P.; Sacquin, Y.; Serreau, J.; Shifrin, G.; Sida, J.L.; Smith, D.; Sordini, V.; Spiro, M.; Stolarczyk, Th.; Suomijdrvi, T.; Tagger, M.; Vangioni, E.; Vauclair, S.; Vial, J.C.; Viaud, B.; Vignaud, D.

2010-01-01

This book is to be read from both ends: one is dedicated to the path towards the infinitely big and the other to the infinitely small. Each path is made of a series of various subject entries illustrating important concepts or achievements in the quest for the understanding of the concerned infinity. For instance the part concerning the infinitely small includes entries like: quarks, Higgs bosons, radiation detection, Chooz neutrinos... while the part for the infinitely big includes: the universe, cosmic radiations, black matter, antimatter... and a series of experiments such as HESS, INTEGRAL, ANTARES, JWST, LOFAR, Planck, LSST, SOHO, Virgo, VLT, or XMM-Newton. This popularization work includes also an important glossary that explains scientific terms used in the entries. (A.C.)

Robust tracking and distributed synchronization control of a multi-motor servomechanism with H-infinity performance.

Science.gov (United States)

Wang, Minlin; Ren, Xuemei; Chen, Qiang

2018-01-01

The multi-motor servomechanism (MMS) is a multi-variable, high coupling and nonlinear system, which makes the controller design challenging. In this paper, an adaptive robust H-infinity control scheme is proposed to achieve both the load tracking and multi-motor synchronization of MMS. This control scheme consists of two parts: a robust tracking controller and a distributed synchronization controller. The robust tracking controller is constructed by incorporating a neural network (NN) K-filter observer into the dynamic surface control, while the distributed synchronization controller is designed by combining the mean deviation coupling control strategy with the distributed technique. The proposed control scheme has several merits: 1) by using the mean deviation coupling synchronization control strategy, the tracking controller and the synchronization controller can be designed individually without any coupling problem; 2) the immeasurable states and unknown nonlinearities are handled by a NN K-filter observer, where the number of NN weights is largely reduced by using the minimal learning parameter technique; 3) the H-infinity performances of tracking error and synchronization error are guaranteed by introducing a robust term into the tracking controller and the synchronization controller, respectively. The stabilities of the tracking and synchronization control systems are analyzed by the Lyapunov theory. Simulation and experimental results based on a four-motor servomechanism are conducted to demonstrate the effectiveness of the proposed method. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

The scalar wave equation in a Schwarzschild space-time

International Nuclear Information System (INIS)

Schmidt, B.G.; Stewart, J.M.

1979-01-01

This paper studies the asymptotic behaviour of solutions of the zero rest mass scalar wave equation in the Schwarzschild space-time in a neighbourhood of spatial infinity which includes parts of future and pass null infinity. The behaviour of such fields is essentially different from that which occurs in a flat space-time. In particular fields which have a Bondi-type expansion in powers of 'r(-1)' near past null infinity do not have such an expansion near future null infinity. Further solutions which have physically reasonable Cauchy data probably fail to have Bondi-type expansions near null infinity. (author)

To infinity and beyond a cultural history of the infinite

CERN Document Server

Maor, Eli

1987-01-01

The infinite! No other question has ever moved so profoundly the spirit of man; no other idea has so fruitfully stimulated his intellect; yet no other concept stands in greater need of clarification than that of the infinite. . . - David Hilbert (1862-1943) Infinity is a fathomless gulf, There is a story attributed to David Hilbert, the preeminent mathe­ into which all things matician whose quotation appears above. A man walked into a vanish. hotel late one night and asked for a room. "Sorry, we don't have o Marcus Aurelius (121- 180), Roman Emperor any more vacancies," replied the owner, "but let's see, perhaps and philosopher I can find you a room after alL" Leaving his desk, the owner reluctantly awakened his guests and asked them to change their rooms: the occupant of room #1 would move to room #2, the occupant of room #2 would move to room #3, and so on until each occupant had moved one room over. To the utter astonish­ ment of our latecomer, room #1 suddenly became vacated, and he happily moved in and...

Playing with infinity of Rózsa Péter. Problem series in a Hungarian tradition of mathematics education.

OpenAIRE

Gosztonyi , Katalin

2016-01-01

International audience; In this paper I present a workshop dedicated to in-service teachers about a special “Hungarian tradition” of mathematics education, focusing on Rózsa Péter's Playing with infinity, a book popularising mathematics (Péter 1944/1961). The workshop in question is part of a three-days teacher training we offer every year since 2012 to secondary teachers of the Parisian region; the teacher training itself is related to an interdisciplinary research project in history of scie...

Is the firewall consistent? Gedanken experiments on black hole complementarity and firewall proposal

International Nuclear Information System (INIS)

Hwang, Dong-il; Lee, Bum-Hoon; Yeom, Dong-han

2013-01-01

In this paper, we discuss the black hole complementarity and the firewall proposal at length. Black hole complementarity is inevitable if we assume the following five things: unitarity, entropy-area formula, existence of an information observer, semi-classical quantum field theory for an asymptotic observer, and the general relativity for an in-falling observer. However, large N rescaling and the AMPS argument show that black hole complementarity is inconsistent. To salvage the basic philosophy of the black hole complementarity, AMPS introduced a firewall around the horizon. According to large N rescaling, the firewall should be located close to the apparent horizon. We investigate the consistency of the firewall with the two critical conditions: the firewall should be near the time-like apparent horizon and it should not affect the future infinity. Concerning this, we have introduced a gravitational collapse with a false vacuum lump which can generate a spacetime structure with disconnected apparent horizons. This reveals a situation that there is a firewall outside of the event horizon, while the apparent horizon is absent. Therefore, the firewall, if it exists, not only does modify the general relativity for an in-falling observer, but also modify the semi-classical quantum field theory for an asymptotic observer

Ward identities of W{sub {infinity}} symmetry and higher-genus amplitudes in 2D string theory

Energy Technology Data Exchange (ETDEWEB)

Hamada, K. [National Lab. for High Energy Physics, Ibaraki (Japan)

1996-03-04

The Ward identities of the W{sub {infinity}} symmetry in two-dimensional string theory in the tachyon background are studied in the continuum approach. We consider amplitudes different from 2D string ones by the external leg factor and derive the recursion relations among them. The recursion relations have non-linear terms which give relations among the amplitudes defined on different genus. The solutions agree with the matrix model results even in higher genus. We also discuss the differences of the roles of the external leg factor between the c{sub M} = 1 model and the c{sub M} <1 model. (orig.).

Semi-discrete approximations to nonlinear systems of conservation laws; consistency and L(infinity)-stability imply convergence. Final report

International Nuclear Information System (INIS)

Tadmor, E.

1988-07-01

A convergence theory for semi-discrete approximations to nonlinear systems of conservation laws is developed. It is shown, by a series of scalar counter-examples, that consistency with the conservation law alone does not guarantee convergence. Instead, a notion of consistency which takes into account both the conservation law and its augmenting entropy condition is introduced. In this context it is concluded that consistency and L(infinity)-stability guarantee for a relevant class of admissible entropy functions, that their entropy production rate belongs to a compact subset of H(loc)sup -1 (x,t). One can now use compensated compactness arguments in order to turn this conclusion into a convergence proof. The current state of the art for these arguments includes the scalar and a wide class of 2 x 2 systems of conservation laws. The general framework of the vanishing viscosity method is studied as an effective way to meet the consistency and L(infinity)-stability requirements. How this method is utilized to enforce consistency and stability for scalar conservation laws is shown. In this context we prove, under the appropriate assumptions, the convergence of finite difference approximations (e.g., the high resolution TVD and UNO methods), finite element approximations (e.g., the Streamline-Diffusion methods) and spectral and pseudospectral approximations (e.g., the Spectral Viscosity methods)

Hawking radiation and propagation of massive charged scalar field on a three-dimensional Gödel black hole

Science.gov (United States)

González, P. A.; Övgün, Ali; Saavedra, Joel; Vásquez, Yerko

2018-06-01

In this paper we consider the three-dimensional Gödel black hole as a background and we study the vector particle tunneling from this background in order to obtain the Hawking temperature. Then, we study the propagation of a massive charged scalar field and we find the quasinormal modes analytically, which turns out be unstable as a consequence of the existence of closed time-like curves. Also, we consider the flux at the horizon and at infinity, and we compute the reflection and transmission coefficients as well as the absorption cross section. Mainly, we show that massive charged scalar waves can be superradiantly amplified by the three-dimensional Gödel black hole and that the coefficients have an oscillatory behavior. Moreover, the absorption cross section is null at the high frequency limit and for certain values of the frequency.

arXiv Hawking radiation and propagation of massive charged scalar field on a three-dimensional G\\"odel black hole

CERN Document Server

González, P.A.; Saavedra, Joel; Vásquez, Yerko

2018-05-18

In this paper we consider the three-dimensional G\\"{o}del black hole as a background and we study the vector particle tunneling from this background in order to obtain the Hawking temperature. Then, we study the propagation of a massive charged scalar field and we find the quasinormal modes analytically, which turns out be unstable as a consequence of the existence of closed time-like curves. Also, we consider the flux at the horizon and at infinity, and we compute the reflection and transmission coefficients as well as the absorption cross section. Mainly, we show that massive charged scalar waves can be superradiantly amplified by the three-dimensional G\\"{o}del black hole and that the coefficients have an oscillatory behavior. Moreover, the absorption cross section is null at the high frequency limit and for certain values of the frequency.

A clinical study of patient acceptance and satisfaction of Varilux Plus and Varilux Infinity lenses.

Science.gov (United States)

Cho, M H; Barnette, C B; Aiken, B; Shipp, M

1991-06-01

An independent study was conducted at the UAB School of Optometry to determine the clinical success with Varilux Plus (Varilux 2) and Varilux Infinity progressive addition lenses (PAL). Two hundred eighty patients (280) were fit between June 1988 and May 1989. The acceptance rate of 97.5 percent was based on the number of lenses ordered versus the number of lenses returned. Patients were contacted by telephone and asked to rate their level of satisfaction with their PALs. A chi-square (non-parametric) test revealed no statistically significant differences in levels of satisfaction with respect to gender, PAL type, or degree of presbyopia. Also, neither refractive error nor previous lens history had a measurable impact on patient satisfaction.

Estimation of uncertainty bounds for the future performance of a power plant

DEFF Research Database (Denmark)

Odgaard, Peter Fogh; Stoustrup, Jakob

2009-01-01

on recent data and the other is based on operating points as well. The third proposed scheme uses dynamical models of the prediction uncertainties, like in H-infinity-control. The proposed schemes are subsequently applied to experimental data from a coal-fired power plant. {Two sets of data from an actual......} the future performance of these plants is that available models of the plants are uncertain. In this paper three schemes for predicting uncertain dynamical systems are presented. The schemes estimate upper and lower bounds on the system performance. Two of the schemes are statistically based, one only based......Prediction of the future performance of large-scale power plants can be very relevant for the operators of these plants, as the predictions can indicate possible problems or failures due to current operating conditions and/or future possible operating conditions. {A problem in predicting...

Asymptotic behaviour of the zeros of the Jacobi polynomials Psub(n)(chi)sup(at,bt) as t→infinity and limit relations of these polynomials with Hermite polynomials

International Nuclear Information System (INIS)

Calogero, F.

1978-01-01

Let zsub(j)(α, β) be the jth zero of the Jacobi polynomial J sub(n)sup(α,β)(z), and xsub(j) the jth zero of the Hermite polynomial Hsub(n)(x). Then, as t→infinity, zsub(j)(at,bt)=(b-a)/(b+a)+t sup(-1/2)c x sub(j)+t -1 4/3(n+1/2+xsub(j) 2 )(a-b)/(a+b) 2 +0(t sup(-3/2)), with c=(ab)sup(1/2) [(a+b)/2]sup(-3/2) a>0, b>0. This formula implies the limit relation n exclamation mark lim sub(t→infinity) [t sup(-n/2)J sub(n)sup(at,bt) ((b-a)/(b+a)+t sup(-1/2)x)] = [(a+b)c/4]sup(n) Hsub(n)(chi/c). (author)

Schroedinger equation from 0 (h/2π) to o(h/2πinfinity)

International Nuclear Information System (INIS)

Voros, A.

1985-08-01

The Balian and Bloch idea, that the semiclassical treatment of the Schroedinger equation can be carried out exactly to all orders, o(h/2πinfinity), has been explicitly confirmed upon the time-independent equation with a polynomial potential V(q) in one degree of freedom. The global analytic structure of certain functions, which encode the full eigenvalue distribution, has indeed been computed in great detail with the complex WKB method, yielding a structure called a resurgence algebra. In the special case V(q) = q 2 sub(M), this leads to sum rules for the eigenvalues, which have been verified numerically. Inasmuch as the leading order 0(h/2π) of the WKB expansion amounts to the stationary phase evaluation of the Feynman path integral, it is a yet unsolved challenge to reproduce our results by an exact analysis of this path integral using a generalized saddle-point treatment

The Political Thinking of Emmanuel Lévinas: A reading of Totality and Infinity

Directory of Open Access Journals (Sweden)

Alejandro Granados-García

2017-02-01

Full Text Available This article explores the political implications of Emmanuel Lévinas thinking (1906-1995, based on a reading of his book Totality and Infinity. It is observed that any political implication and thought in Lévinas work counts with an ethical basis, that, in turn, is configured based on the idea of Infinite and the metaphysical Desire of the Other that gives rise to. The thinking of this philosopher of Lithuanian origin invites us to recover humanity and, in consequence, to not allow that inhumanity takes hold of our interactions, starting from a subjectivity capable of taking care of the Other in an ethical way. This requires searching for concrete strategies for establishing, in everyday life, political relations of hospitality and respect for plurality. Starting from an anthropology of fragility, there is no other way than putting in common our fragilities and, in doing so, ensure to create a world habitable among-all.

A new deformation of W-infinity and applications to the two-loop WZNW and conformal affine Toda models

International Nuclear Information System (INIS)

Aratyn, H.; Ferreira, L.A.; Gomes, J.F.; Zimerman, A.H.

1992-01-01

We constructed a center less W-infinity type of algebra in terms of a generator of a center less Virasoro algebra and an Abelian spin-1 current. This algebra conventionally emerges in the study of pseudo-differential operators on a circle or alternatively within KP hierarchy with Watanabe's bracket. Construction used here is based on a special deformation of the algebra w ∞ of area preserving diffeomorphisms of a 2-manifold. We show that this deformation technique applies to the two-loop WZNW and conformal affine Toda models, establishing henceforth W ∞ invariance of these models. (author)

Remarks on a Class of Nonlinear Schrödinger Equations with Potential Vanishing at Infinity

Directory of Open Access Journals (Sweden)

Hongbo Zhu

2013-01-01

Full Text Available We study the following nonlinear Schrödinger equation −Δu+V(xu=K(xf(u,  x∈ℝN,  u∈H1(ℝN, where the potential V(x vanishes at infinity. Working in weighted Sobolev space, we obtain the ground states of problem ( under a Nahari type condition. Furthermore, if V(x,K(x are radically symmetric with respect to x∈ℝN, it is shown that problem ( has a positive solution with some more general growth conditions of the nonlinearity. Particularly, if f(u=up, then the growth restriction σ≤p≤N+2/N-2 in Ambrosetti et al. (2005 can be relaxed to σ~≤p≤N+2/N-2, where σ~<σ if 0<β<α<2.

An axisymmetric evolution code for the Einstein equations on hyperboloidal slices

International Nuclear Information System (INIS)

Rinne, Oliver

2010-01-01

We present the first stable dynamical numerical evolutions of the Einstein equations in terms of a conformally rescaled metric on hyperboloidal hypersurfaces extending to future null infinity. Axisymmetry is imposed in order to reduce the computational cost. The formulation is based on an earlier axisymmetric evolution scheme, adapted to time slices of constant mean curvature. Ideas from a previous study by Moncrief and the author are applied in order to regularize the formally singular evolution equations at future null infinity. Long-term stable and convergent evolutions of Schwarzschild spacetime are obtained, including a gravitational perturbation. The Bondi news function is evaluated at future null infinity.

Beyond the classical theory of heat conduction: a perspective view of future from entropy

Science.gov (United States)

Lai, Xiang; Zhu, Pingan

2016-01-01

Energy is conserved by the first law of thermodynamics; its quality degrades constantly due to entropy generation, by the second law of thermodynamics. It is thus important to examine the entropy generation regarding the way to reduce its magnitude and the limit of entropy generation as time tends to infinity regarding whether it is bounded or not. This work initiates such an analysis with one-dimensional heat conduction. The work not only offers some fundamental insights of universe and its future, but also builds up the relation between the second law of thermodynamics and mathematical inequalities via developing the latter of either new or classical nature. A concise review of entropy is also included for the interest of performing the analysis in this work and the similar analysis for other processes in the future. PMID:27843400

Mixed H-Infinity and Passive Filtering for Discrete Fuzzy Neural Networks With Stochastic Jumps and Time Delays.

Science.gov (United States)

Shi, Peng; Zhang, Yingqi; Chadli, Mohammed; Agarwal, Ramesh K

2016-04-01

In this brief, the problems of the mixed H-infinity and passivity performance analysis and design are investigated for discrete time-delay neural networks with Markovian jump parameters represented by Takagi-Sugeno fuzzy model. The main purpose of this brief is to design a filter to guarantee that the augmented Markovian jump fuzzy neural networks are stable in mean-square sense and satisfy a prescribed passivity performance index by employing the Lyapunov method and the stochastic analysis technique. Applying the matrix decomposition techniques, sufficient conditions are provided for the solvability of the problems, which can be formulated in terms of linear matrix inequalities. A numerical example is also presented to illustrate the effectiveness of the proposed techniques.

Axially symmetric Lorentzian wormholes in general relativity

International Nuclear Information System (INIS)

Schein, F.

1997-11-01

The field equations of Einstein's theory of general relativity, being local, do not fix the global structure of space-time. They admit topologically non-trivial solutions, including spatially closed universes and the amazing possibility of shortcuts for travel between distant regions in space and time - so-called Lorentzian wormholes. The aim of this thesis is to (mathematically) construct space-times which contain traversal wormholes connecting arbitrary distant regions of an asymptotically flat or asymptotically de Sitter universe. Since the wormhole mouths appear as two separate masses in the exterior space, space-time can at best be axially symmetric. We eliminate the non-staticity caused by the gravitational attraction of the mouths by anchoring them by strings held at infinity or, alternatively, by electric repulsion. The space-times are obtained by surgically grafting together well-known solutions of Einstein's equations along timelike hypersurfaces. This surgery naturally concentrates a non-zero stress-energy tensor on the boundary between the two space-times which can be investigated by using the standard thin shell formalism. It turns out that, when using charged black holes, the provided constructions are possible without violation of any of the energy conditions. In general, observers living in the axially symmetric, asymptotically flat (respectively asymptotically de Sitter) region axe able to send causal signals through the topologically non-trivial region. However, the wormhole space-times contain closed timelike curves. Because of this explicit violation of global hyperbolicity these models do not serve as counterexamples to known topological censorship theorems. (author)

Non-fragile robust stabilization and H{sub {infinity}} control for uncertain stochastic nonlinear time-delay systems

Energy Technology Data Exchange (ETDEWEB)

Zhang Jinhui [Department of Automatic Control, Beijing Institute of Technology, Beijing 100081 (China)], E-mail: jinhuizhang82@gmail.com; Shi Peng [Faculty of Advanced Technology, University of Glamorgan, Pontypridd CF37 1DL (United Kingdom); ILSCM, School of Science and Engineering, Victoria University, Melbourne, Vic. 8001 (Australia); School of Mathematics and Statistics, University of South Australia, Mawson Lakes, SA 5095 (Australia)], E-mail: pshi@glam.ac.uk; Yang Hongjiu [Department of Automatic Control, Beijing Institute of Technology, Beijing 100081 (China)], E-mail: yanghongjiu@gmail.com

2009-12-15

This paper deals with the problem of non-fragile robust stabilization and H{sub {infinity}} control for a class of uncertain stochastic nonlinear time-delay systems. The parametric uncertainties are real time-varying as well as norm bounded. The time-delay factors are unknown and time-varying with known bounds. The aim is to design a memoryless non-fragile state feedback control law such that the closed-loop system is stochastically asymptotically stable in the mean square and the effect of the disturbance input on the controlled output is less than a prescribed level for all admissible parameter uncertainties. New sufficient conditions for the existence of such controllers are presented based on the linear matrix inequalities (LMIs) approach. Numerical example is given to illustrate the effectiveness of the developed techniques.

Cutkosky rules for superstring field theory

International Nuclear Information System (INIS)

Pius, Roji; Sen, Ashoke

2016-01-01

Superstring field theory expresses the perturbative S-matrix of superstring theory as a sum of Feynman diagrams each of which is manifestly free from ultraviolet divergences. The interaction vertices fall off exponentially for large space-like external momenta making the ultraviolet finiteness property manifest, but blow up exponentially for large time-like external momenta making it impossible to take the integration contours for loop energies to lie along the real axis. This forces us to carry out the integrals over the loop energies by choosing appropriate contours in the complex plane whose ends go to infinity along the imaginary axis but which take complicated form in the interior navigating around the various poles of the propagators. We consider the general class of quantum field theories with this property and prove Cutkosky rules for the amplitudes to all orders in perturbation theory. Besides having applications to string field theory, these results also give an alternative derivation of Cutkosky rules in ordinary quantum field theories.

First law of AdS black holes in higher curvature gravity

International Nuclear Information System (INIS)

Koga, Jun-ichirou

2005-01-01

We consider the first law of black hole thermodynamics in an asymptotically anti-de Sitter spacetime in the class of gravitational theories whose gravitational Lagrangian is an arbitrary function of the Ricci scalar. We first show that the conserved quantities in this class of gravitational theories constructed through conformal completion remain unchanged under the conformal transformation into the Einstein frame. We then prove that the mass and the angular momenta defined by these conserved quantities, along with the entropy defined by the Noether charge, satisfy the first law of black hole thermodynamics, not only in Einstein gravity but also in the higher curvature gravity within the class under consideration. We also point out that it is naturally understood in the symplectic formalism that the mass satisfying the first law should be necessarily defined associated with the timelike Killing vector nonrotating at infinity. Finally, a possible generalization into a wider class of gravitational theories is discussed

SU(N) gauge theory couplings on asymmetric lattices

International Nuclear Information System (INIS)

Karsch, F.

1982-01-01

The connection between euclidean and hamiltonian lattice QCD requires the use of asymmetric lattices, which in turn implies the necessity of two coupling parameters. We analyse the dependence of space- and time-like couplings gsub(sigma) and gsub(tau) on the different lattice spacings a and asub(tau) in space and time directions. Using the background field method we determine the derivatives of the couplings with respect to the asymmetry factor xi = a/asub(tau) in the weak coupling limit, obtaining for xi = 1 the values (deltag -2 sub(sigma)/deltaxi)sub(xi = 1) = 0.11403, N = 2, 0.20161, N = 3, (deltag -2 sub(tau)/deltaxi)sub(xi = 1) = -0.06759, N = 2, -0.13195, N = 3. We argue that the sum of these derivatives has to be equal to b 0 = 11N/48π 2 and determine the Λ parameter for asymmetric lattices. In the limit xi → infinity all our results agree with those of A. and P. Hasenfratz. (orig.)

Thermal comparison of Infiniti OZil and Signature Ellips phacoemulsification systems.

Science.gov (United States)

Schmutz, Joseph S; Olson, Randall J

2010-05-01

To determine thermal characteristics of Signature Ellips (Abbott Medical Optics) and Infiniti OZil (Alcon, Inc.) transverse ultrasound and compare both with longitudinal ultrasound in clinically relevant scenarios. Laboratory investigation. Temperature increase over baseline after 60 seconds was measured in water at positions in 90-degree increments around the sleeve near the proximal needle shaft in an artificial chamber for Ellips and OZil on continuous ultrasound with aspiration blocked and unblocked. This was also done with Signature using longitudinal ultrasound, with and without micropulse (6 ms on, 12 ms off), with aspiration blocked and unblocked, and at the OZil sleeve tip on continuous transverse mode with aspiration unblocked. OZil (8.1 +/- 0.3 C) had greater temperature increase than Ellips (5.2 +/- 0.3 C; P < .0001) with aspiration unblocked and blocked (29.3 +/- 1.0 C vs 12.2 +/- 0.7 C; P < .0001). OZil had uneven distribution of heat around the shaft (30.1 +/- 0.5 C vs 28.5 +/- 0.6 C; P < .0001), whereas Ellips did not (P = .57). OZil was cooler at the tip (6.6 +/- 0.2 C; P < .0001). Friction in a cadaver eye incision only increased these numbers by 10% (OZil, irrigation blocked). Metal stress probably creates heat at the proximal needle junction for both transverse methods. Heat generation differences between OZil and Ellips result from the manner in which they create needle motion. Incision burns may occur, especially for OZil, under nonpulsed settings during fragment removal with occlusion when reaching across the anterior chamber such that the proximal needle shaft came near the wound. Copyright 2010 Elsevier Inc. All rights reserved.

Class of continuous timelike curves determines the topology of spacetime

International Nuclear Information System (INIS)

Malament, D.B.

1977-01-01

The title assertion is proven, and two corollaries are established. First, the topology of every past and future distinguishing spacetime is determined by its causal structure. Second, in every spacetime the path topology of Hawking, King, and McCarthy codes topological, differential, and conformal structure

Remark on Trautman's Radiation Condition

International Nuclear Information System (INIS)

Walker, M.

1979-01-01

The confusion about the boundary conditions for radiating systems formulated by Trautman are discussed. The confusion has mainly to do with where in space-time the conditions are to be imposed but also with what is it that the conditions are intended to guarantee. Imposing Trautman's conditions near future null infinity allows the existence of outgoing radiation; in order to exclude incoming radiation, they must be imposed near (or at) past null infinity. Since receding to infinity in spacelike directions means that one crosses all radiation, whether in- or outgoing, it makes no sense to impose the conditions at spatial infinity. If one were to impose fall-off of the electromagnetic field in flat space-time of 1/n at spatial infinity, then the field would contain finite energy. (Auth.)

Minimal conditions for the existence of a Hawking-like flux

International Nuclear Information System (INIS)

Barcelo, Carlos; Liberati, Stefano; Sonego, Sebastiano; Visser, Matt

2011-01-01

We investigate the minimal conditions that an asymptotically flat general relativistic spacetime must satisfy in order for a Hawking-like Planckian flux of particles to arrive at future null infinity. We demonstrate that there is no requirement that any sort of horizon form anywhere in the spacetime. We find that the irreducible core requirement is encoded in an approximately exponential 'peeling' relationship between affine coordinates on past and future null infinity. As long as a suitable adiabaticity condition holds, then a Planck-distributed Hawking-like flux will arrive at future null infinity with temperature determined by the e-folding properties of the outgoing null geodesics. The temperature of the Hawking-like flux can slowly evolve as a function of time. We also show that the notion of peeling of null geodesics is distinct from the usual notion of 'inaffinity' used in Hawking's definition of surface gravity.

Testing of a JEF-1 based WIMS-D cross section library for migration area and k-infinity predictions for LWHCR lattices

International Nuclear Information System (INIS)

Pelloni, S.; Stepanek, J.

1987-01-01

The cell code WIMSD4 is used for the analysis of PROTEUS-LWHCR experiments. A library for this code which is based on the European evaluation JEF-1 was produced at EIR using the Los Alamos NJOY system with its module WIMSR and the Canadian management code WILMA. In general, this library delivered more accurate eigenvalues and reaction rates than the WIMS-Standard and WIMS81 libraries did in comparison to experimental values from PROTEUS-LWHCR Cores 1-3. However, large discrepancies (up to about 10%) occured between calculated migration areas (M 2 ). Additional investigations have been undertaken to clarify this problem, since theoretical M 2 -values are needed for deducing k-infinity in the experiments. This has been done in the context of calculations for a reference LWHCR test lattice. The following major reasons for these deviations were found. First, the self-scattering term in non-moderators (P 0 matrix) in the JEF-1 library was not transport corrected. Second, Standard and JEF-1 libraries use infinite dilute cross sections for 238 U, whereas the WIMS81 library uses fully shielded cross sections. Third, the standard library uses the 'row' formula for the transport correction, whereas the 'inflow' formula is applied in the case of JEF-1 and WIMS81 libraries. Lastly, oxygen and 238 U scattering cross sections in the fast energy range are smaller in the case of the WIMS81 library. Differences in calculated k-infinity values between the currently used library and WIMS81 (up to 3%) come (in order of importance for the reference LWHCR lattice) mainly from resonance cross sections for 240 Pu capture, 238 U capture and 239 Pu fission. Recommendations have been made for generating a new JEF-1 library using updated versions of WIMSR and WILMA. (author)

The collisional Penrose process

Science.gov (United States)

Schnittman, Jeremy D.

2018-06-01

Shortly after the discovery of the Kerr metric in 1963, it was realized that a region existed outside of the black hole's event horizon where no time-like observer could remain stationary. In 1969, Roger Penrose showed that particles within this ergosphere region could possess negative energy, as measured by an observer at infinity. When captured by the horizon, these negative energy particles essentially extract mass and angular momentum from the black hole. While the decay of a single particle within the ergosphere is not a particularly efficient means of energy extraction, the collision of multiple particles can reach arbitrarily high center-of-mass energy in the limit of extremal black hole spin. The resulting particles can escape with high efficiency, potentially serving as a probe of high-energy particle physics as well as general relativity. In this paper, we briefly review the history of the field and highlight a specific astrophysical application of the collisional Penrose process: the potential to enhance annihilation of dark matter particles in the vicinity of a supermassive black hole.

The energy and the linear momentum of space-times in general relativity

International Nuclear Information System (INIS)

Schoen, R.; Yau, S.T.

1981-01-01

We extend our previous proof of the positive mass conjecture to allow a more general asymptotic condition proposed by York. Hence we are able to prove that for an isolated physical system, the energy momentum four vector is a future timelike vector unless the system is trivial. Furthermore, we allow singularities of the type of black holes. (orig.)

The Infinity Puzzle - The story of the Higgs Boson:From QED to the LHC via Higgs and the Gang of Six

CERN Multimedia

CERN. Geneva

2013-01-01

Rutherford and Bohr discovered the nuclear atom 100 years ago. Roughly 50 years ago a theory of this basic structure of matter was inspired by the work of Peter Higgs and others. In July 2012 the discovery "beyond reasonable doubt" of Higgs's boson, and the experimental proof of the theory, was announced and speculations about Nobel prizes mushroomed. The Economist said of Frank Close's book, The Infinity Puzzle (OUP,2012): "The Nobel Committee would be well advised to read Mr Close’s book before making their decision." This pedagogic talk reviews the ideas and the history, and assesses how the credits should be shared. The conclusions may not be what you anticipate

The scalar wave equation in a Schwarzschild spacetime

International Nuclear Information System (INIS)

Stewart, J.M.; Schmidt, B.G.

1978-09-01

This paper studies the asymptotic behaviour of solutions of the zero rest mass scalar wave equation in the Schwarzschild spacetime in a neighbourhood of spatial infinity, which includes parts of future and past null infinity. The behaviour of such fields is essentially different from that which accurs in a flat spacetime. (orig.) [de

Four-dimensional symmetry from a broad viewpoint. II Invariant distribution of quantized field oscillators and questions on infinities

Science.gov (United States)

Hsu, J. P.

1983-01-01

The foundation of the quantum field theory is changed by introducing a new universal probability principle into field operators: one single inherent and invariant probability distribution P(/k/) is postulated for boson and fermion field oscillators. This can be accomplished only when one treats the four-dimensional symmetry from a broad viewpoint. Special relativity is too restrictive to allow such a universal probability principle. A radical length, R, appears in physics through the probability distribution P(/k/). The force between two point particles vanishes when their relative distance tends to zero. This appears to be a general property for all forces and resembles the property of asymptotic freedom. The usual infinities in vacuum fluctuations and in local interactions, however complicated they may be, are all removed from quantum field theories. In appendix A a simple finite and unitary theory of unified electroweak interactions is discussed without assuming Higgs scalar bosons.

Axisymmetric core collapse simulations using characteristic numerical relativity

International Nuclear Information System (INIS)

Siebel, Florian; Mueller, Ewald; Font, Jose A.; Papadopoulos, Philippos

2003-01-01

We present results from nonrotating axisymmetric stellar core collapse simulations in general relativity. Our hydrodynamics code has proved robust and accurate enough to allow for a detailed analysis of the global dynamics of the collapse. Contrary to traditional approaches based on the 3+1 formulation of the gravitational field equations, our framework uses a foliation based on a family of outgoing light cones, emanating from a regular center, and terminating at future null infinity. Such a coordinate system is well adapted to the study of interesting dynamical spacetimes in relativistic astrophysics such as stellar core collapse and neutron star formation. Perhaps most importantly this procedure allows for the extraction of gravitational waves at future null infinity, along with the commonly used quadrupole formalism for the gravitational wave extraction. Our results concerning the gravitational wave signals show noticeable disagreement when those are extracted by computing the Bondi news at future null infinity on the one hand and by using the quadrupole formula on the other hand. We have a strong indication that for our setup the quadrupole formula on the null cone does not lead to physical gravitational wave signals. The Bondi gravitational wave signals extracted at infinity show typical oscillation frequencies of about 0.5 kHz

Hawking radiation from quasilocal dynamical horizons

Indian Academy of Sciences (India)

A black hole is usually described to be a region of space–time where the gravitational attraction is so high that even light cannot escape to infinity. This notion, that light can- not escape to future null infinity, is an appropriate characterization of a black hole in asymptotically flat space–time. In asymptotically flat space–times, ...

A thermodynamically consistent quasi-particle model without temperature-dependent infinity of the vacuum zero point energy

International Nuclear Information System (INIS)

Cao Jing; Jiang Yu; Sun Weimin; Zong Hongshi

2012-01-01

In this Letter, an improved quasi-particle model is presented. Unlike the previous approach of establishing quasi-particle model, we introduce a classical background field (it is allowed to depend on the temperature) to deal with the infinity of thermal vacuum energy which exists in previous quasi-particle models. After taking into account the effect of this classical background field, the partition function of quasi-particle system can be made well-defined. Based on this and following the standard ensemble theory, we construct a thermodynamically consistent quasi-particle model without the need of any reformulation of statistical mechanics or thermodynamical consistency relation. As an application of our model, we employ it to the case of (2+1) flavor QGP at zero chemical potential and finite temperature and obtain a good fit to the recent lattice simulation results of Borsányi et al. A comparison of the result of our model with early calculations using other models is also presented. It is shown that our method is general and can be generalized to the case where the effective mass depends not only on the temperature but also on the chemical potential.

Interior metric and ray-tracing map in the firework black-to-white hole transition

OpenAIRE

Rovelli, Carlo; Martin-Dussaud, Pierre

2018-01-01

The possibility that a black hole could tunnel into to white hole has recently received attention. Here we present a metric that improves the "firework" metric: it describes the entire process and solves the Einstein's equations everywhere except on a small transition surface that corresponds to the quantum tunneling. We compute the corresponding ray-tracing map from past infinity to future infinity explicitly.

Cosmological horizons and reconstruction of quantum field theories

International Nuclear Information System (INIS)

Dappiaggi, C.; Pinamonti, N.

2007-12-01

As a starting point for this manuscript, we remark how the cosmological horizon of a certain class of Friedmann-Robertson-Walker backgrounds shares some non trivial geometric properties with null infinity in an asymptotically flat spacetime. Such a feature is generalized to a larger class of expanding spacetimes M admitting a geodesically complete cosmological horizon J - common to all co-moving observers. This property is later exploited in order to recast, in a cosmological background, some recent results for a linear scalar quantum field theory in spacetimes asymptotically flat at null infinity. Under suitable hypotheses on M - valid for de Sitter spacetime and some other FRW spacetimes obtained by perturbing deSitter space - the algebra of observables for a Klein-Gordon field is mapped into a subalgebra of the algebra of observables W(J - ) constructed on the cosmological horizon. There is exactly one pure quasifree state λ on W(J - ) which fulfills a suitable energy positivity condition with respect to a generator related with the cosmological time displacements. Furthermore λ induces a preferred physically meaningful quantum state λ M for the quantum theory in the bulk. If M admits a timelike Killing generator preserving J - , then the associated self-adjoint generator in the GNS representation of λ M has positive spectrum (i.e. energy). Moreover λ M turns out to be invariant under every symmetry of the bulk metric which preserves the cosmological horizon. In the case of an expanding de Sitter spacetime, λ M coincides with the Euclidean (Bunch-Davies) vacuum state, hence being Hadamard in this case. Remarks on the validity of the Hadamard property for λ M in more general spacetimes are presented. (orig.)

Prospective study of Centurion® versus Infiniti® phacoemulsification systems: surgical and visual outcomes.

Science.gov (United States)

Oh, Lawrence J; Nguyen, Chu Luan; Wong, Eugene; Wang, Samuel S Y; Francis, Ian C

2017-01-01

To evaluate surgical outcomes (SOs) and visual outcomes (VOs) in cataract surgery comparing the Centurion ® phacoemulsification system (CPS) with the Infiniti ® phacoemulsification system (IPS). Prospective, consecutive study in a single-site private practice. Totally 412 patients undergoing cataract surgery with either the CPS using the 30-degree balanced ® tip ( n =207) or the IPS using the 30-degree Kelman ® tip ( n =205). Intraoperative and postoperative outcomes were documented prospectively up to one month follow-up. Nuclear sclerosis (NS) grade, cumulated dissipated energy (CDE), preoperative corrected distance visual acuity (CDVA), and CDVA at one month were recorded. CDE was 13.50% less in the whole CPS compared with the whole IPS subcohort. In eyes with NS grade III or greater, CDE was 28.87% less with CPS ( n =70) compared with IPS ( n =44) ( P =0.010). Surgical complications were not statistically different between the two subcohorts ( P =0.083), but in the one case of vitreous loss using the CPS, CDVA of 6/4 was achieved at one month. The mean CDVAs (VOs) at one month for NS grade III and above cataracts were -0.17 logMAR (6/4.5) in the CPS and -0.15 logMAR (6/4.5) in the IPS subcohort respectively ( P =0.033). CDE is 28.87% less, and VOs are significantly improved, in denser cataracts in the CPS compared with the IPS. The authors recommend the CPS for cases with denser nuclei.

Dispelling Black Hole Pathologies Through Theory and Observation

Directory of Open Access Journals (Sweden)

Spivey R. J.

2015-10-01

Full Text Available Astrophysical black holes are by now routinely identified with metrics representing eter- nal black holes obtained as exact mathematical solutions of Einstein’s field equations. However, the mere existence and discovery of stationary solutions is no guarantee that they can be attained through dynamical processes. If a straightforward physical caveat is respected throughout a spacetime manifold then the ingress of matter across an event horizon is prohibited, in accordance with Einstein’s expectation. As black hole forma- tion and growth would be inhibited, the various pathological traits of black holes such as information loss, closed timelike curves and singularities of infinite mass density would be obviated. Gravitational collapse would not terminate with the formation of black holes possessing event horizons but asymptotically slow as the maximal time dilation between any pair of worldlines tends towards infinity. The remnants might be better described as dark holes, often indistinguishable from black holes except in certain as- trophysically important cases. The absence of trapped surf aces circumvents topological censorship, with potentially observable consequences for astronomy, as exemplified by the remarkable electromagnetic characteristics, extreme energetics and abrupt extinc- tion of quasars within low redshift galaxies.

Stationary strings near a higher-dimensional rotating black hole

International Nuclear Information System (INIS)

Frolov, Valeri P.; Stevens, Kory A.

2004-01-01

We study stationary string configurations in a space-time of a higher-dimensional rotating black hole. We demonstrate that the Nambu-Goto equations for a stationary string in the 5D (five-dimensional) Myers-Perry metric allow a separation of variables. We present these equations in the first-order form and study their properties. We prove that the only stationary string configuration that crosses the infinite redshift surface and remains regular there is a principal Killing string. A worldsheet of such a string is generated by a principal null geodesic and a timelike at infinity Killing vector field. We obtain principal Killing string solutions in the Myers-Perry metrics with an arbitrary number of dimensions. It is shown that due to the interaction of a string with a rotating black hole, there is an angular momentum transfer from the black hole to the string. We calculate the rate of this transfer in a space-time with an arbitrary number of dimensions. This effect slows down the rotation of the black hole. We discuss possible final stationary configurations of a rotating black hole interacting with a string

Prospective study of Centurion® versus Infiniti® phacoemulsification systems: surgical and visual outcomes

Directory of Open Access Journals (Sweden)

Lawrence J. Oh

2017-11-01

Full Text Available AIM: To evaluate surgical outcomes (SOs and visual outcomes (VOs in cataract surgery comparing the Centurion® phacoemulsification system (CPS with the Infiniti® phacoemulsification system (IPS. METHODS: Prospective, consecutive study in a single-site private practice. Totally 412 patients undergoing cataract surgery with either the CPS using the 30-degree balanced® tip (n=207 or the IPS using the 30-degree Kelman® tip (n=205. Intraoperative and postoperative outcomes were documented prospectively up to one month follow-up. Nuclear sclerosis (NS grade, cumulated dissipated energy (CDE, preoperative corrected distance visual acuity (CDVA, and CDVA at one month were recorded. RESULTS: CDE was 13.50% less in the whole CPS compared with the whole IPS subcohort. In eyes with NS grade III or greater, CDE was 28.87% less with CPS (n=70 compared with IPS (n=44 (P=0.010. Surgical complications were not statistically different between the two subcohorts (P=0.083, but in the one case of vitreous loss using the CPS, CDVA of 6/4 was achieved at one month. The mean CDVAs (VOs at one month for NS grade III and above cataracts were -0.17 logMAR (6/4.5 in the CPS and -0.15 logMAR (6/4.5 in the IPS subcohort respectively (P=0.033. CONCLUSION: CDE is 28.87% less, and VOs are significantly improved, in denser cataracts in the CPS compared with the IPS. The authors recommend the CPS for cases with denser nuclei.

From Here and Now to Infinity and Eternity: A Message to New Medical Doctors*

Science.gov (United States)

Lapeña, José Florencio F.

2014-01-01

Commencement means both an end and a beginning; the end of the academic year and the beginning of the rest of your life as new physicians. For such a beginning, it is useful to view it in retrospect, from the point of view of the end, by conducting a pre-mortem on your life. Taking the existentialist (ex sistere, to stand forth) stance, each of us can be classified into one of four basic types of person, based on our characteristic space and time (or spatio-temporal) context or horizon. Our space can be limited to the “here” and our time to the “now;” or our space may extend to “infinity” and our time embark on “eternity.” In-between these poles, most have space contexts rooted in their home and work “turf” and time involving their “lifetime,” while some expand their space to include the “world” and their time to encompass “history.” From the “here and now” and “turf and lifetime” contexts, the horizons of “world and history,” and “infinity and eternity” are examined, challenging new medical doctors to realize their full potential. The new physician is exhorted not to wait for a post-mortem to define (des finitus, to set limits) his or her life. He or she should stand forth, to live, and give life. The new medical doctor is encouraged to look to the sunrise, draw strength from the sunshine, to be brave, and strong and true. PMID:24891804

Cosmological horizons and reconstruction of quantum field theories

Energy Technology Data Exchange (ETDEWEB)

Dappiaggi, C.; Pinamonti, N. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik]|[Trento Univ., Povo (Italy). Istituto Nazionale di Alta Matematica ' ' F. Severi' ' - GNFM; Moretti, V. [Trento Univ. (Italy). Dipt. di Matematica]|[Istituto Nazionale di Fisica Nucleare - Gruppo Collegato di Trento, Povo (Italy)

2007-12-15

As a starting point for this manuscript, we remark how the cosmological horizon of a certain class of Friedmann-Robertson-Walker backgrounds shares some non trivial geometric properties with null infinity in an asymptotically flat spacetime. Such a feature is generalized to a larger class of expanding spacetimes M admitting a geodesically complete cosmological horizon J{sup -} common to all co-moving observers. This property is later exploited in order to recast, in a cosmological background, some recent results for a linear scalar quantum field theory in spacetimes asymptotically flat at null infinity. Under suitable hypotheses on M - valid for de Sitter spacetime and some other FRW spacetimes obtained by perturbing deSitter space - the algebra of observables for a Klein-Gordon field is mapped into a subalgebra of the algebra of observables W(J{sup -}) constructed on the cosmological horizon. There is exactly one pure quasifree state {lambda} on W(J{sup -}) which fulfills a suitable energy positivity condition with respect to a generator related with the cosmological time displacements. Furthermore {lambda} induces a preferred physically meaningful quantum state {lambda}{sub M} for the quantum theory in the bulk. If M admits a timelike Killing generator preserving J{sup -}, then the associated self-adjoint generator in the GNS representation of {lambda}{sub M} has positive spectrum (i.e. energy). Moreover {lambda}{sub M} turns out to be invariant under every symmetry of the bulk metric which preserves the cosmological horizon. In the case of an expanding de Sitter spacetime, {lambda}{sub M} coincides with the Euclidean (Bunch-Davies) vacuum state, hence being Hadamard in this case. Remarks on the validity of the Hadamard property for {lambda}{sub M} in more general spacetimes are presented. (orig.)

Synthesis and X-ray crystal structure of (OsO(3)F(2))(2)2XeOF(4) and the Raman spectra of (OsO(3)F(2))(infinity), (OsO(3)F(2))(2), and (OsO(3)F(2))(2)2XeOF(4).

Science.gov (United States)

Hughes, Michael J; Mercier, Hélène P A; Schrobilgen, Gary J

2009-05-18

The adduct, (OsO(3)F(2))(2)2XeOF(4), was synthesized by dissolution of the infinite chain polymer, (OsO(3)F(2))(infinity), in XeOF(4) solvent at room temperature followed by removal of excess XeOF(4) under dynamic vacuum at 0 degrees C. Continued pumping at 0 degrees C resulted in removal of associated XeOF(4), yielding (OsO(3)F(2))(2), a new low-temperature phase of OsO(3)F(2). Upon standing at 25 degrees C for 1(1)/(2) h, (OsO(3)F(2))(2) underwent a phase transition to the known monoclinic phase, (OsO(3)F(2))(infinity). The title compounds, (OsO(3)F(2))(infinity), (OsO(3)F(2))(2), and (OsO(3)F(2))(2)2XeOF(4) have been characterized by low-temperature (-150 degrees C) Raman spectroscopy. Crystallization of (OsO(3)F(2))(2)2XeOF(4) from XeOF(4) solution at 0 degrees C yielded crystals suitable for X-ray structure determination. The structural unit contains the (OsO(3)F(2))(2) dimer in which the OsO(3)F(3) units are joined by two Os---F---Os bridges having fluorine bridge atoms that are equidistant from the osmium centers (2.117(5) and 2.107(4) A). The dimer coordinates to two XeOF(4) molecules through Os-F...Xe bridges in which the Xe...F distances (2.757(5) A) are significantly less than the sum of the Xe and F van der Waals radii (3.63 A). The (OsO(3)F(2))(2) dimer has C(i) symmetry in which each pseudo-octahedral OsO(3)F(3) unit has a facial arrangement of oxygen ligands with XeOF(4) molecules that are only slightly distorted from their gas-phase C(4v) symmetry. Quantum-chemical calculations using SVWN and B3LYP methods were employed to calculate the gas-phase geometries, natural bond orbital analyses, and vibrational frequencies of (OsO(3)F(2))(2), (OsO(3)F(2))(2)2XeOF(4), XeOF(4), OsO(2)F(4), and (mu-FOsO(3)F(2))(2)OsO(3)F(-) to aid in the assignment of the experimental vibrational frequencies of (OsO(3)F(2))(2), (OsO(3)F(2))(2)2XeOF(4), and (OsO(3)F(2))(infinity). The vibrational modes of the low-temperature polymeric phase, (OsO(3)F(2))(infinity), have been

Generating geodesic flows and supergravity solutions

NARCIS (Netherlands)

Bergshoeff, E.; Chemissany, W.; Ploegh, A.; Trigiante, M.; Van Riet, T.

2009-01-01

We consider the geodesic motion on the symmetric moduli spaces that arise after timelike and spacellike reductions of supergravity theories. The geodesics correspond to timelike respectively spacelike p-brane Solutions when they are lifted over a p-dimensional flat space. In particular, we consider

LPV H-infinity Control for the Longitudinal Dynamics of a Flexible Air-Breathing Hypersonic Vehicle

Science.gov (United States)

Hughes, Hunter Douglas

This dissertation establishes the method needed to synthesize and simulate an Hinfinity Linear Parameter-Varying (LPV) controller for a flexible air-breathing hypersonic vehicle model. A study was conducted to gain the understanding of the elastic effects on the open loop system. It was determined that three modes of vibration would be suitable for the hypersonic vehicle model. It was also discovered from the open loop study that there is strong coupling in the hypersonic vehicle states, especially between the angle of attack, pitch rate, pitch attitude, and the exible modes of the vehicle. This dissertation outlines the procedure for synthesizing a full state feedback Hinfinity LPV controller for the hypersonic vehicle. The full state feedback study looked at both velocity and altitude tracking for the exible vehicle. A parametric study was conducted on each of these controllers to see the effects of changing the number of gridding points in the parameter space and changing the parameter variation rate limits in the system on the robust performance of the controller. As a result of the parametric study, a 7 x 7 grid ranging from Mach 7 to Mach 9 in velocity and from 70,000 feet to 90,000 feet in altitude, and a parameter variation rate limit of [.5 200]T was used for both the velocity tracking and altitude tracking cases. The resulting Hinfinity robust performances were gamma = 2.2224 for the velocity tracking case and = 1:7582 for the altitude tracking case. A linear analysis was then conducted on five different selected trim points from the Hinfinity LPV controller. This was conducted for the velocity tracking and altitude tracking cases. The results of linear analysis show that there is a slight difference in the response of the Hinfinity LPV controller and the fixed point H infinity controller. For the tracking task, the Hinfinity controller responds more quickly, and has a lower Hinfinity performance value. Next, the H infinity LPV controller was simulated

The sky pattern of the linearized gravitational memory effect

International Nuclear Information System (INIS)

Mädler, Thomas; Winicour, Jeffrey

2016-01-01

The gravitational memory effect leads to a net displacement in the relative positions of test particles. This memory is related to the change in the strain of the gravitational radiation field between infinite past and infinite future retarded times. There are three known sources of the memory effect: (i) the loss of energy to future null infinity by massless fields or particles, (ii) the ejection of massive particles to infinity from a bound system and (iii) homogeneous, source-free gravitational waves. In the context of linearized theory, we show that asymptotic conditions controlling these known sources of the gravitational memory effect rule out any other possible sources with physically reasonable stress–energy tensors. Except for the source-free gravitational waves, the two other known sources produce gravitational memory with E -mode radiation strain, characterized by a certain curl-free sky pattern of their polarization. Thus our results show that the only known source of B -mode gravitational memory is of primordial origin, corresponding in the linearized theory to a homogeneous wave entering from past null infinity. (paper)

Possible energy dependence of Θ13 in neutrino oscillations

International Nuclear Information System (INIS)

Klinkhamer, Frans R.

2005-01-01

A simple three-flavor neutrino-oscillation model is discussed which has both nonzero mass differences and timelike Fermi-point splittings, together with a combined bi-maximal and trimaximal mixing pattern. One possible consequence would be new effects in ν μ →ν e oscillations, characterized by an energy-dependent effective mixing angle Θ 13 . Future experiments such as T2K and NOνA, and perhaps even the current MINOS experiment, could look for these effects

Reconstruction of orientation of stresses acting in infinity within the Kovdor ore body based on field determinations

Directory of Open Access Journals (Sweden)

Rybin V. V.

2017-03-01

Full Text Available Mining Institute KSC RAS has conducted research which aim is to study the possibilities of increasing the tilt angles of pit walls in massifs of solid rock. One of the problems the solution of which will contribute to achieving this goal is to determine the direction of the maximum component of principal stresses in intact massif on the "infinity" necessary to work out mathematical models of rock massif including quarry recess. To solve this problem it has been proposed to use the results of parameters' measurement of stress state by the unloading method in near-wall rock massif. The basic research of near-wall rock massif has been conducted on mine quarry "Zhelezny" (JSC "Kovdor ore processing plant". The measurements have been performed by the discharge method in option of end measurements directly from the quarry ledges on special observation stations using horizontal wells. The direction of maximum compression acting in sub-meridional course in the Kovdor apatiteshtafelyte-baddeleite deposit (the Kovdor ore cluster has been determined by the conformal mapping method on the basis of experimental estimations of stress parameters in the rock massif. The results obtained are of great importance for assessing a level of stresses acting directly in a near open-pit zone. They are applied to set boundary conditions when modeling stress-strain state of near-wall rock massif and assess slope stability.

Pharmacogenetic testing for clopidogrel using the rapid INFINITI analyzer: a dose-escalation study.

Science.gov (United States)

Gladding, Patrick; White, Harvey; Voss, Jamie; Ormiston, John; Stewart, Jim; Ruygrok, Peter; Bvaldivia, Badi; Baak, Ruth; White, Catherine; Webster, Mark

2009-11-01

Our aim was to assess whether a higher clopidogrel maintenance dose has a greater antiplatelet effect in CYP2C19*2 allele carriers compared with noncarriers. Clopidogrel is a prodrug that is biotransformed by the cytochrome P450 enzymes CYP2C19, 2C9, and 3A4, 2B6, 1A2. The CYPC219*2 loss of function variant has been associated with a reduced antiplatelet response to clopidogrel and a 3-fold risk of stent thrombosis. Forty patients on standard maintenance dosage clopidogrel (75 mg), for 9.4 +/- 9.2 weeks, were enrolled into a dose escalation study. Platelet function was assessed at baseline and after 1 week of 150 mg once daily using the VerifyNow platelet function analyzer (Accumetrics Ltd., San Diego, California). Genomic DNA was hybridized to a BioFilmChip microarray on the INFINITI analyzer (AutoGenomics Inc., Carlsbad, California) and analyzed for the CYP19*2, *4, *17, and CYP2C9*2, *3 polymorphisms. Platelet inhibition increased over 1 week, mean +8.6 +/- 13.5% (p = 0.0003). Carriers of the CYP2C19*2 allele had significantly reduced platelet inhibition at baseline (median 18%, range 0% to 72%) compared with wildtype (wt) (median 59%, range 11% to 95%, p = 0.01) and at 1 week (p = 0.03). CYP2C19*2 allele carriers had an increase in platelet inhibition of (mean +9 +/- 11%, p = 0.03) and reduction in platelet reactivity (mean -26 +/- 38 platelet response unit, p = 0.04) with a higher dose. Together CYP2C19*2 and CYP2C9*3 loss of function carriers had a greater change in platelet inhibition with 150 mg daily than wt/wt (+10.9% vs. +0.7%, p = 0.04). Increasing the dose of clopidogrel in patients with nonresponder polymorphisms can increase antiplatelet response. Personalizing clopidogrel dosing using pharmacogenomics may be an effective method of optimizing treatment.

Progress report on the k{sub infinity} measurements of HTGR type lattices with the oscillation technique at zero reactivity; Rapport d'advancement sur les mesures de K {sub infinite} des reseaux du type HTGR avec la technique de l'oscillateur a'reactivite' nulle

Energy Technology Data Exchange (ETDEWEB)

NONE

1971-01-15

The principles of measuring k {sub infinity} for a HTGR lattice using the oscillation technique with zero reactivity were already presented at the ''9th reactor physics meeting of countries participating in the Dragon project''. A brief summary of the essential characteristics of the experiment is followed by a status report on present work.

SoLID-SIDIS: Future Measurements of Transversity, TMDs and more

Energy Technology Data Exchange (ETDEWEB)

Ye, Zhihong [Duke University, Durham, NC

2015-09-01

Over the past few decades, investigations of the nucleon structure mainly focused on the one-dimensional study of parton distributions and structure functions. New theoretical developments, including both transverse momentum distributions (TMDs) and generalized parton distributions (GPDs), provide a new way to understand the 3-dimensional structure of the nucleon. TMDs give access to the nucleon tomography in the momentum space, and also provide an opportunity to evaluate the contribution of quarks’ and gluons’ orbital angular momenta to the nucleon spin. The experimental study of TMDs requires a device with high luminosity, large kinematic coverage and great detection resolutions. With the Jefferson Lab (JLab) 12 GeV electron beam, we have proposed a Solenoidal Large Intensity Device (SoLID) in Hall A which is capable of performing such measurements. Several newly approved experiments will perform measurements of both the single and double spin asymmetries via semi-inclusive deep inelastic scattering (SIDIS) from polarized ³He ("neutron") and proton targets. The new data will provide important information to extract TMDs with unprecedented precision. Besides, we are also able to use SoLID to explore many more important physics topics. Several experiments for the measurements of PVDIS and J=y production have been approved, and new proposals are under development. For example, with the similar SIDIS configuration, we are actively developing new measurements to study GPDs via deep virtual Compton scattering (DVCS) with polarized targets, doubly-DVCS, deep virtual meson production, time-like Compton scattering, and so on. Our collaboration has submitted the pre-conceptual design report to JLab and successfully passed the Director’s Review in early 2015. Our collaborators are focusing on optimizing the detector system, finalizing the detector designs and proceeding on the detector R&D. We are looking forward to having the DOE Science Review in the near

Asymptotically simple spacetimes and mass loss due to gravitational waves

Science.gov (United States)

Saw, Vee-Liem

The cosmological constant Λ used to be a freedom in Einstein’s theory of general relativity (GR), where one had a proclivity to set it to zero purely for convenience. The signs of Λ or Λ being zero would describe universes with different properties. For instance, the conformal structure of spacetime directly depends on Λ: null infinity ℐ is a spacelike, null, or timelike hypersurface, if Λ > 0, Λ = 0, or Λ 0 in Einstein’s theory of GR. A quantity that depends on the conformal structure of spacetime, especially on the nature of ℐ, is the Bondi mass which in turn dictates the mass loss of an isolated gravitating system due to energy carried away by gravitational waves. This problem of extending the Bondi mass to a universe with Λ > 0 has spawned intense research activity over the past several years. Some aspects include a closer inspection on the conformal properties, working with linearization, attempts using a Hamiltonian formulation based on “linearized” asymptotic symmetries, as well as obtaining the general asymptotic solutions of de Sitter-like spacetimes. We consolidate on the progress thus far from the various approaches that have been undertaken, as well as discuss the current open problems and possible directions in this area.

Machian effects in general relativity

International Nuclear Information System (INIS)

Embacher, F.

1988-01-01

As a consequence of Mach's principle, rotating matter should cause local inertial frames or gyroscopes in its vicinity to undergo a small rotation which is not present in the Newtonian picture. H. Thirring and J. Lense were the first to derive similar predictions from the field equations of general relativity. Since these early days of relativity, a lot of exact and approximate solutions to Einstein's equations have been examined under this point of view. The qualitative features of Machian effects are most easily demonstrated in the cylinder symmetric case, where some exact results are available. For example, space-time is flat inside a uniformly rotating matter shell, and the rotation of this interior with respect to 'infinity' (the distant stars) has a clear meaning. In the more realistic case of what happens near a massive rotating star, one is forced to perform certain approximations. In modern language, Machian effects are described in terms of the twist of timelike killing vector fields. In the linearized theory, the equations that determine the Machian structure generated by a given matter distribution, resemble to some extent those of classical electrodynamics. This correspondence provides a pedagogical approach how to compute the quantitative extent of inertial frame 'dragging'. 6 refs., 5 figs. (Author)

Feasibility studies for accessing nucleon structure observables with the PANDA experiment at the future FAIR facility

International Nuclear Information System (INIS)

Mora Espi, Maria Carmen

2012-10-01

The availability of a high-intensity antiproton beam with momentum up to 15 GeV/c at the future Facility for Antiproton and Ion Research (FAIR) will open a unique opportunity to investigate wide areas of nuclear physics with the PANDA (antiProton ANnihilations at DArmstadt) detector. Part of these investigations concern the Electromagnetic Form Factors of the proton in the time-like region and the study of the transition distribution amplitudes, for which feasibility studies have been performed in this thesis. Moreover, simulations to study the efficiency and the energy resolution of the backward endcap of the electromagnetic calorimeter of PANDA are presented. This detector is crucial especially for the reconstruction of processes like anti pp→e + e - π 0 , investigated in this work. Different arrangements of dead material were studied. The results show that both, the efficiency and the energy resolution of the backward endcap of the electromagnetic calorimeter fulfill the requirements for the detection of backward particles, and that this detector is necessary for the reconstruction of the channels of interest. The study of the annihilation channel anti pp→e + e - will improve the knowledge of the electromagnetic form factors in the time-like region, and will help to understand their connection with the electromagnetic form factors in the space-like region. In this thesis the feasibility of a measurement of the anti pp→e + e - cross section with PANDA is studied using Monte-Carlo simulations. The major background channel anti pp→π + π - is taken into account. The results show a 10 9 background suppression factor, which assure a sufficiently clean signal with less than 0.1 % background contamination. The signal can be measured with an efficiency greater than 30 % up to s=14 (GeV/c) 2 . The Electromagnetic Form Factors are extracted from the reconstructed signal and corrected angular distribution. Above this s limit, the low cross section will not allow

Future foam: Nontrivial topology from bubble collisions in eternal inflation

International Nuclear Information System (INIS)

Bousso, Raphael; Freivogel, Ben; Yang, I-S.; Sekino, Yasuhiro; Shenker, Stephen; Susskind, Leonard; Yeh, C.-P.

2008-01-01

We study pocket universes which have zero cosmological constant and nontrivial boundary topology. These arise from bubble collisions in eternal inflation. Using a simplified dust model of collisions we find that boundaries of any genus can occur. Using a radiation shell model we perform analytic studies in the thin-wall limit to show the existence of geometries with a single toroidal boundary. We give plausibility arguments that higher genus boundaries can also occur. In geometries with one boundary of any genus a timelike observer can see the entire boundary. Geometries with multiple disconnected boundaries can also occur. In the spherical case with two boundaries the boundaries are separated by a horizon. Our results suggest that the holographic dual description for eternal inflation, proposed by Freivogel, Sekino, Susskind and Yeh, should include summation over the genus of the base space of the dual conformal field theory. We point out peculiarities of this genus expansion compared to the string perturbation series.

Integrazione di tecniche informatiche per la conservazione della Memoria Storica. Il centro urbano di S. Pietro Infine.

Directory of Open Access Journals (Sweden)

Michela Cigola

2012-11-01

Full Text Available La sperimentazione che si presenta in questo articolo è un corollario delle esperienze condotte con le ricerche PRIN 2006 e PRIN 2008, che avevano come focus l’uso e l’approfondimento dei Sistemi Informativi territoriali, che il nostro gruppo ha testato a diverse scale trovando in essi un validissimo supporto all’analisi ed al rilievo. Abbiamo pensato di far dialogare i sistemi GIS con la tecnologia laser scanner, strumenti uno per rappresentare e l’altro per rilevare basandoci sul fatto che entrambi gli approcci operativi, GIS e Scanner Laser trattano elementi topologici [punti] proiettati in determinati Datum cartografici. In sintesi si propone di individuare una procedura in grado di confrontare/leggere il modello 3D-Digital Surface Model (DSM, risultato dell’elaborazione della nuvola di punti georeferenziati acquisiti con la scansione, all’interno di strutture G.I.S. verificando la possibilità di associare ad esso, banche di dati complesse con contenuti che riguardano anche gli elementi del rilievo tradizionale. In questo modo si tenta di informatizzare la conoscenza singolare e sistemica di architetture o nuclei urbani e la rappresentazione con modelli 3D interattivi risultati di un rilievo strumentale. La sperimentazione sarà condotta sul centro urbano di San Pietro Infine, in provincia di Caserta, tessuto urbano di grande interesse, poiché è rimasto immutato dal momento in cui fu distrutto dai bombardamenti alleati durante l’ultima guerra.

The Black Hole Radiation in Massive Gravity

Directory of Open Access Journals (Sweden)

Ivan Arraut

2018-02-01

Full Text Available We apply the Bogoliubov transformations in order to connect two different vacuums, one located at past infinity and another located at future infinity around a black hole inside the scenario of the nonlinear theory of massive gravity. The presence of the extra degrees of freedom changes the behavior of the logarithmic singularity and, as a consequence, the relation between the two Bogoliubov coefficients. This has an effect on the number of particles, or equivalently, on the black hole temperature perceived by observers defining the time arbitrarily.

Non-Abelian, supersymmetric black holes and strings in 5 dimensions

International Nuclear Information System (INIS)

Meessen, Patrick; Ortín, Tomás; Ramírez, Pedro F.

2016-01-01

We construct and study the first supersymmetric black-hole and black-string solutions of non-Abelian-gauged N=1,d=5 supergravity (N=1,d=5 Super-Einstein-Yang-Mills theory) with non-trivial SU(2) gauge fields: BPST instantons for black holes and BPS monopoles of different kinds (’t Hooft-Polyakov, Wu-Yang and Protogenov) for black strings and also for certain black holes that are well defined solutions only for very specific values of all the moduli. Instantons, as well as colored monopoles do not contribute to the masses and tensions but do contribute to the entropies. The construction is based on the characterization of the supersymmetric solutions of gauged N=1,d=5 supergravity coupled to vector multiplets achieved in ref. http://dx.doi.org/10.1088/1126-6708/2007/08/096 which we elaborate upon by finding the rules to construct supersymmetric solutions with one additional isometry, both for the timelike and null classes. These rules automatically connect the timelike and null non-Abelian supersymmetric solutions of N=1,d=5 SEYM theory with the timelike ones of N=2,d=4 SEYM theory http://dx.doi.org/10.1103/PhysRevD.78.065031; http://dx.doi.org/10.1088/1126-6708/2008/09/099 by dimensional reduction and oxidation. In the timelike-to-timelike case the singular Kronheimer reduction recently studied in ref. http://dx.doi.org/10.1016/j.physletb.2015.04.065 plays a crucial role.

Evolutionary paths, applications and future development of discrete event simulation systems; Simulazione a eventi discreti: nuove linee di sviluppo e applicazioni

Energy Technology Data Exchange (ETDEWEB)

Garetti, M. [Milan Politecnico, Milan (Italy). Dipt. di Economia e Produzione; Bartolotta, A.

2000-10-01

The state of the art of discrete event simulation tools is presented with special reference to the application to the manufacturing systems area. After presenting the basics of discrete event computer simulation, the different steps to be followed for the successful use of simulation are defined and discussed. The evolution of software packages for discrete event simulation is also presented, highlighting main technological changes. Finally the future development lines of simulation are outlined. [Italian] Viene presentato lo stato dell'arte della simulazione a eventi discreti. Dopo una breve descrizione della tecnica della simulazione e della sua evoluzione, con un particolare riguardo alla simulazione dei sistemi produttivi, sono descritte le fasi della procedura da seguire per condurre unostudio di simulazione e i possibili approcci per la costruzione del modello. Viene infine descritta l'evoluzione dei principali pacchetti software di simulazione esistenti sul mercato.

H(infinity)/H(2)/Kalman filtering of linear dynamical systems via variational techniques with applications to target tracking

Science.gov (United States)

Rawicz, Paul Lawrence

In this thesis, the similarities between the structure of the H infinity, H2, and Kalman filters are examined. The filters used in this examination have been derived through duality to the full information controller. In addition, a direct variation of parameters derivation of the Hinfinity filter is presented for both continuous and discrete time (staler case). Direct and controller dual derivations using differential games exist in the literature and also employ variational techniques. Using a variational, rather than a differential games, viewpoint has resulted in a simple relationship between the Riccati equations that arise from the derivation and the results of the Bounded Real Lemma. This same relation has previously been found in the literature and used to relate the Riccati inequality for linear systems to the Hamilton Jacobi inequality for nonlinear systems when implementing the Hinfinity controller. The Hinfinity, H2, and Kalman filters are applied to the two-state target tracking problem. In continuous time, closed form analytic expressions for the trackers and their performance are determined. To evaluate the trackers using a neutral, realistic, criterion, the probability of target escape is developed. That is, the probability that the target position error will be such that the target is outside the radar beam width resulting in a loss of measurement. In discrete time, a numerical example, using the probability of target escape, is presented to illustrate the differences in tracker performance.

Wormholes and timetravel

International Nuclear Information System (INIS)

Aichelburg, P.C.; Schein, F.

1998-01-01

We discuss a construction of a wormhole with the following properties: the wormhole connects to the same asymptotic region and is one-way traversable i.e. there exist timelike curves that start and end in the same asymptotic region and go through the wormhole. Moreover it is possible to satisfy the energy conditions. From any point in the asymptotic region there exist closed timelike curves. (author)

Cosmic baldness

International Nuclear Information System (INIS)

Boucher, W.; Gibbons, G.W.

1983-01-01

Some years ago it was suggested that solutions of Einstein's equations with a positive cosmological term should eventually settle down to a state which is stationary inside the cosmological event horizon of any future inextendible timelike curve. This stationary state, it was suggested, would, if no black holes were present, be de Sitter space. The recent work on the inflationary scenario in the early universe has reawakened interest in this topic and the purpose of this article is to review the mechanism whereby a universe dominated by vacuum energy. (author)

Causal inheritance in plane wave quotients

International Nuclear Information System (INIS)

Hubeny, Veronika E.; Rangamani, Mukund; Ross, Simon F.

2003-01-01

We investigate the appearance of closed timelike curves in quotients of plane waves along spacelike isometries. First we formulate a necessary and sufficient condition for a quotient of a general spacetime to preserve stable causality. We explicitly show that the plane waves are stably causal; in passing, we observe that some pp-waves are not even distinguishing. We then consider the classification of all quotients of the maximally supersymmetric ten-dimensional plane wave under a spacelike isometry, and show that the quotient will lead to closed timelike curves iff the isometry involves a translation along the u direction. The appearance of these closed timelike curves is thus connected to the special properties of the light cones in plane wave spacetimes. We show that all other quotients preserve stable causality

Causal inheritance in plane wave quotients

Science.gov (United States)

Hubeny, Veronika E.; Rangamani, Mukund; Ross, Simon F.

2004-01-01

We investigate the appearance of closed timelike curves in quotients of plane waves along spacelike isometries. First we formulate a necessary and sufficient condition for a quotient of a general space-time to preserve stable causality. We explicitly show that the plane waves are stably causal; in passing, we observe that some pp waves are not even distinguishing. We then consider the classification of all quotients of the maximally supersymmetric ten-dimensional plane wave under a spacelike isometry, and show that the quotient will lead to closed timelike curves iff the isometry involves a translation along the u direction. The appearance of these closed timelike curves is thus connected to the special properties of the light cones in plane wave space-times. We show that all other quotients preserve stable causality.

Total angular momentum from Dirac eigenspinors

International Nuclear Information System (INIS)

Szabados, Laszlo B

2008-01-01

The eigenvalue problem for Dirac operators, constructed from two connections on the spinor bundle over closed spacelike 2-surfaces, is investigated. A class of divergence-free vector fields, built from the eigenspinors, are found, which, for the lowest eigenvalue, reproduce the rotation Killing vectors of metric spheres, and provide rotation BMS vector fields at future null infinity. This makes it possible to introduce a well-defined, gauge invariant spatial angular momentum at null infinity, which reduces to the standard expression in stationary spacetimes. The general formula for the angular momentum flux carried away by the gravitational radiation is also derived

Feasibility studies for accessing nucleon structure observables with the PANDA experiment at the future FAIR facility

Energy Technology Data Exchange (ETDEWEB)

Mora Espi, Maria Carmen

2012-10-15

The availability of a high-intensity antiproton beam with momentum up to 15 GeV/c at the future Facility for Antiproton and Ion Research (FAIR) will open a unique opportunity to investigate wide areas of nuclear physics with the PANDA (antiProton ANnihilations at DArmstadt) detector. Part of these investigations concern the Electromagnetic Form Factors of the proton in the time-like region and the study of the transition distribution amplitudes, for which feasibility studies have been performed in this thesis. Moreover, simulations to study the efficiency and the energy resolution of the backward endcap of the electromagnetic calorimeter of PANDA are presented. This detector is crucial especially for the reconstruction of processes like anti pp{yields}e{sup +}e{sup -}{pi}{sup 0}, investigated in this work. Different arrangements of dead material were studied. The results show that both, the efficiency and the energy resolution of the backward endcap of the electromagnetic calorimeter fulfill the requirements for the detection of backward particles, and that this detector is necessary for the reconstruction of the channels of interest. The study of the annihilation channel anti pp{yields}e{sup +}e{sup -} will improve the knowledge of the electromagnetic form factors in the time-like region, and will help to understand their connection with the electromagnetic form factors in the space-like region. In this thesis the feasibility of a measurement of the anti pp{yields}e{sup +}e{sup -} cross section with PANDA is studied using Monte-Carlo simulations. The major background channel anti pp{yields}{pi}{sup +}{pi}{sup -} is taken into account. The results show a 10{sup 9} background suppression factor, which assure a sufficiently clean signal with less than 0.1 % background contamination. The signal can be measured with an efficiency greater than 30 % up to s=14 (GeV/c){sup 2}. The Electromagnetic Form Factors are extracted from the reconstructed signal and corrected

A Comparative Study of Standardized Infinity Reference and Average Reference for EEG of Three Typical Brain States

Directory of Open Access Journals (Sweden)

Gaoxing Zheng

2018-03-01

Full Text Available The choice of different reference electrodes plays an important role in deciphering the functional meaning of electroencephalography (EEG signals. In recent years, the infinity zero reference using the reference electrode standard technique (REST has been increasingly applied, while the average reference (AR was generally advocated as the best available reference option in previous classical EEG studies. Here, we designed EEG experiments and performed a direct comparison between the influences of REST and AR on EEG-revealed brain activity features for three typical brain behavior states (eyes-closed, eyes-open and music-listening. The analysis results revealed the following observations: (1 there is no significant difference in the alpha-wave-blocking effect during the eyes-open state compared with the eyes-closed state for both REST and AR references; (2 there was clear frontal EEG asymmetry during the resting state, and the degree of lateralization under REST was higher than that under AR; (3 the global brain functional connectivity density (FCD and local FCD have higher values for REST than for AR under different behavior states; and (4 the value of the small-world network characteristic in the eyes-closed state is significantly (in full, alpha, beta and gamma frequency bands higher than that in the eyes-open state, and the small-world effect under the REST reference is higher than that under AR. In addition, the music-listening state has a higher small-world network effect than the eyes-closed state. The above results suggest that typical EEG features might be more clearly presented by applying the REST reference than by applying AR when using a 64-channel recording.

A novel multi-model probability battery state of charge estimation approach for electric vehicles using H-infinity algorithm

International Nuclear Information System (INIS)

Lin, Cheng; Mu, Hao; Xiong, Rui; Shen, Weixiang

2016-01-01

Highlights: • A novel multi-model probability battery SOC fusion estimation approach was proposed. • The linear matrix inequality-based H∞ technique is employed to estimate the SOC. • The Bayes theorem has been employed to realize the optimal weight for the fusion. • The robustness of the proposed approach is verified by different batteries. • The results show that the proposed method can promote global estimation accuracy. - Abstract: Due to the strong nonlinearity and complex time-variant property of batteries, the existing state of charge (SOC) estimation approaches based on a single equivalent circuit model (ECM) cannot provide the accurate SOC for the entire discharging period. This paper aims to present a novel SOC estimation approach based on a multiple ECMs fusion method for improving the practical application performance. In the proposed approach, three battery ECMs, namely the Thevenin model, the double polarization model and the 3rd order RC model, are selected to describe the dynamic voltage of lithium-ion batteries and the genetic algorithm is then used to determine the model parameters. The linear matrix inequality-based H-infinity technique is employed to estimate the SOC from the three models and the Bayes theorem-based probability method is employed to determine the optimal weights for synthesizing the SOCs estimated from the three models. Two types of lithium-ion batteries are used to verify the feasibility and robustness of the proposed approach. The results indicate that the proposed approach can improve the accuracy and reliability of the SOC estimation against uncertain battery materials and inaccurate initial states.

D-branes in a big bang/big crunch universe: Nappi-Witten gauged WZW model

Energy Technology Data Exchange (ETDEWEB)

Hikida, Yasuaki [School of Physics and BK-21 Physics Division, Seoul National University, Seoul 151-747 (Korea, Republic of); Nayak, Rashmi R. [Dipartimento di Fisica and INFN, Sezione di Roma 2, ' Tor Vergata' ' , Rome 00133 (Italy); Panigrahi, Kamal L. [Dipartimento di Fisica and INFN, Sezione di Roma 2, ' Tor Vergata' , Rome 00133 (Italy)

2005-05-01

We study D-branes in the Nappi-Witten model, which is a gauged WZW model based on (SL(2,R) x SU(2))/(U(1) x U(1)). The model describes a four dimensional space-time consisting of cosmological regions with big bang/big crunch singularities and static regions with closed time-like curves. The aim of this paper is to investigate by D-brane probes whether there are pathologies associated with the cosmological singularities and the closed time-like curves. We first classify D-branes in a group theoretical way, and then examine DBI actions for effective theories on the D-branes. In particular, we show that D-brane metric from the DBI action does not include singularities, and wave functions on the D-branes are well behaved even in the presence of closed time-like curves.

How many 'times' do we have in quantum gravity?

International Nuclear Information System (INIS)

Hosoya, Akio; Soda, Jiro.

1990-07-01

Apparently, there are infinite number of time-like variables in the Wheeler-DeWitt equation in quantum gravity. This gives rise to an obvious conceptual difficulty and further becomes an obstacle if one wants to canonically third quantize the universe. In this paper, adopting York's gauge in the path-integral approach, we formulate quantum geometrodynamics so that it contains only a single time-like variable corresponding to the total volume of the universe. (author)

Kaluza-Klein theories and the signature of space-time

International Nuclear Information System (INIS)

Aref'eva, I.Ya.; Volovich, I.V.

1985-06-01

Higher-dimensional Kaluza-Klein theories with extra compactified time-like variables are considered. Topological criteria are presented for a compact manifold which prevent the appearance of massless ghosts in an effective four-dimensional theory. Some models are given in which these criteria hold. Among them is the bosonic sector of the low-energy limit of the anomaly-free superstring theories. As a rule, the extra time-like variables lead to compactification with a compact hyperbolic manifold. (author)

Next-to-next-to-leading order evolution of non-singlet fragmentation functions

International Nuclear Information System (INIS)

Mitov, A.; Moch, S.; Vogt, A.

2006-04-01

We have investigated the next-to-next-to-leading order (NNLO) corrections to inclusive hadron production in e + e - annihilation and the related parton fragmentation distributions, the 'time-like' counterparts of the 'space-like' deep-inelastic structure functions and parton densities. We have re-derived the corresponding second-order coefficient functions in massless perturbative QCD, which so far had been calculated only by one group. Moreover we present, for the first time, the third-order splitting functions governing the NNLO evolution of flavour non-singlet fragmentation distributions. These results have been obtained by two independent methods relating time-like quantities to calculations performed in deep-inelastic scattering. We briefly illustrate the numerical size of the NNLO corrections, and make a prediction for the difference of the yet unknown time-like and space-like splitting functions at the fourth order in the strong coupling constant. (Orig.)

Supersymmetric warped AdS in extended topologically massive supergravity

International Nuclear Information System (INIS)

Deger, N.S.; Kaya, A.; Samtleben, H.; Sezgin, E.

2014-01-01

We determine the most general form of off-shell N=(1,1) supergravity field configurations in three dimensions by requiring that at least one off-shell Killing spinor exists. We then impose the field equations of the topologically massive off-shell supergravity and find a class of solutions whose properties crucially depend on the norm of the auxiliary vector field. These are spacelike-squashed and timelike-stretched AdS 3 for the spacelike and timelike norms, respectively. At the transition point where the norm vanishes, the solution is null warped AdS 3 . This occurs when the coefficient of the Lorentz–Chern–Simons term is related to the AdS radius by μℓ=2. We find that the spacelike-squashed AdS 3 can be modded out by a suitable discrete subgroup of the isometry group, yielding an extremal black hole solution which avoids closed timelike curves

Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR

CERN Document Server

Singh, B.; Krusche, B.; Steinacher, M.; Walford, N.; Liu, B.; Liu, H.; Liu, Z.; Shen, X.; Wang, C.; Zhao, J.; Albrecht, M.; Erlen, T.; Fink, M.; Heinsius, F.; Held, T.; Holtmann, T.; Jasper, S.; Keshk, I.; Koch, H.; Kopf, B.; Kuhlmann, M.; Kümmel, M.; Leiber, S.; Mikirtychyants, M.; Musiol, P.; Mustafa, A.; Pelizäus, M.; Pychy, J.; Richter, M.; Schnier, C.; Schröder, T.; Sowa, C.; Steinke, M.; Triffterer, T.; Wiedner, U.; Ball, M.; Beck, R.; Hammann, C.; Ketzer, B.; Kube, M.; Mahlberg, P.; Rossbach, M.; Schmidt, C.; Schmitz, R.; Thoma, U.; Urban, M.; Walther, D.; Wendel, C.; Wilson, A.; Bianconi, A.; Bragadireanu, M.; Caprini, M.; Pantea, D.; Patel, B.; Czyzycki, W.; Domagala, M.; Filo, G.; Jaworowski, J.; Krawczyk, M.; Lisowski, F.; Lisowski, E.; Michałek, M.; Poznański, P.; Płażek, J.; Korcyl, K.; Kozela, A.; Kulessa, P.; Lebiedowicz, P.; Pysz, K.; Schäfer, W.; Szczurek, A.; Fiutowski, T.; Idzik, M.; Mindur, B.; Przyborowski, D.; Swientek, K.; Biernat, J.; Kamys, B.; Kistryn, S.; Korcyl, G.; Krzemien, W.; Magiera, A.; Moskal, P.; Pyszniak, A.; Rudy, Z.; Salabura, P.; Smyrski, J.; Strzempek, P.; Wronska, A.; Augustin, I.; Böhm, R.; Lehmann, I.; Marinescu, D. Nicmorus; Schmitt, L.; Varentsov, V.; Al-Turany, M.; Belias, A.; Deppe, H.; Dzhygadlo, R.; Ehret, A.; Flemming, H.; Gerhardt, A.; Götzen, K.; Gromliuk, A.; Gruber, L.; Karabowicz, R.; Kliemt, R.; Krebs, M.; Kurilla, U.; Lehmann, D.; Löchner, S.; Lühning, J.; Lynen, U.; Orth, H.; Patsyuk, M.; Peters, K.; Saito, T.; Schepers, G.; Schmidt, C.J.; Schwarz, C.; Schwiening, J.; Täschner, A.; Traxler, M.; Ugur, C.; Voss, B.; Wieczorek, P.; Wilms, A.; Zühlsdorf, M.; Abazov, V.; Alexeev, G.; Arefiev, V.A.; Astakhov, V.; Barabanov, M. Yu.; Batyunya, B.V.; Davydov, Y.; Dodokhov, V. Kh.; Efremov, A.; Fechtchenko, A.; Fedunov, A.G.; Galoyan, A.; Grigoryan, S.; Koshurnikov, E.K.; Lobanov, Y. Yu.; Lobanov, V.I.; Makarov, A.F.; Malinina, L.V.; Malyshev, V.; Olshevskiy, A.G.; Perevalova, E.; Piskun, A.A.; Pocheptsov, T.; Pontecorvo, G.; Rodionov, V.; Rogov, Y.; Salmin, R.; Samartsev, A.; Sapozhnikov, M.G.; Shabratova, G.; Skachkov, N.B.; Skachkova, A.N.; Strokovsky, E.A.; Suleimanov, M.; Teshev, R.; Tokmenin, V.; Uzhinsky, V.; Vodopianov, A.; Zaporozhets, S.A.; Zhuravlev, N.I.; Zorin, A.G.; Branford, D.; Glazier, D.; Watts, D.; Böhm, M.; Britting, A.; Eyrich, W.; Lehmann, A.; Pfaffinger, M.; Uhlig, F.; Dobbs, S.; Seth, K.; Tomaradze, A.; Xiao, T.; Bettoni, D.; Carassiti, V.; Cotta Ramusino, A.; Dalpiaz, P.; Drago, A.; Fioravanti, E.; Garzia, I.; Savrie, M.; Akishina, V.; Kisel, I.; Kozlov, G.; Pugach, M.; Zyzak, M.; Gianotti, P.; Guaraldo, C.; Lucherini, V.; Bersani, A.; Bracco, G.; Macri, M.; Parodi, R.F.; Biguenko, K.; Brinkmann, K.; Di Pietro, V.; Diehl, S.; Dormenev, V.; Drexler, P.; Düren, M.; Etzelmüller, E.; Galuska, M.; Gutz, E.; Hahn, C.; Hayrapetyan, A.; Kesselkaul, M.; Kühn, W.; Kuske, T.; Lange, J.S.; Liang, Y.; Metag, V.; Nanova, M.; Nazarenko, S.; Novotny, R.; Quagli, T.; Reiter, S.; Rieke, J.; Rosenbaum, C.; Schmidt, M.; Schnell, R.; Stenzel, H.; Thöring, U.; Ullrich, M.; Wagner, M.N.; Wasem, T.; Wohlfahrt, B.; Zaunick, H.; Ireland, D.; Rosner, G.; Seitz, B.; Deepak, P.N.; Kulkarni, A.; Apostolou, A.; Babai, M.; Kavatsyuk, M.; Lemmens, P.J.; Lindemulder, M.; Loehner, H.; Messchendorp, J.; Schakel, P.; Smit, H.; Tiemens, M.; van der Weele, J.C.; Veenstra, R.; Vejdani, S.; Dutta, K.; Kalita, K.; Kumar, A.; Roy, A.; Sohlbach, H.; Bai, M.; Bianchi, L.; Büscher, M.; Cao, L.; Cebulla, A.; Dosdall, R.; Gillitzer, A.; Goldenbaum, F.; Grunwald, D.; Herten, A.; Hu, Q.; Kemmerling, G.; Kleines, H.; Lehrach, A.; Nellen, R.; Ohm, H.; Orfanitski, S.; Prasuhn, D.; Prencipe, E.; Pütz, J.; Ritman, J.; Schadmand, S.; Sefzick, T.; Serdyuk, V.; Sterzenbach, G.; Stockmanns, T.; Wintz, P.; Wüstner, P.; Xu, H.; Zambanini, A.; Li, S.; Li, Z.; Sun, Z.; Rigato, V.; Isaksson, L.; Achenbach, P.; Corell, O.; Denig, A.; Distler, M.; Hoek, M.; Karavdina, A.; Lauth, W.; Merkel, H.; Müller, U.; Pochodzalla, J.; Sanchez, S.; Schlimme, S.; Sfienti, C.; Thiel, M.; Ahmadi, H.; Ahmed, S.; Bleser, S.; Capozza, L.; Cardinali, M.; Dbeyssi, A.; Deiseroth, M.; Feldbauer, F.; Fritsch, M.; Fröhlich, B.; Jasinski, P.; Kang, D.; Khaneft, D.; Klasen, R.; Leithoff, H.H.; Lin, D.; Maas, F.; Maldaner, S.; Marta, M.; Michel, M.; Espí, M. C. Mora; Morales Morales, C.; Motzko, C.; Nerling, F.; Noll, O.; Pflüger, S.; Pitka, A.; Piñeiro, D. Rodríguez; Sanchez-Lorente, A.; Steinen, M.; Valente, R.; Weber, T.; Zambrana, M.; Zimmermann, I.; Fedorov, A.; Korjik, M.; Missevitch, O.; Boukharov, A.; Malyshev, O.; Marishev, I.; Balanutsa, V.; Balanutsa, P.; Chernetsky, V.; Demekhin, A.; Dolgolenko, A.; Fedorets, P.; Gerasimov, A.; Goryachev, V.; Chandratre, V.; Datar, V.; Dutta, D.; Jha, V.; Kumawat, H.; Mohanty, A.K.; Parmar, A.; Roy, B.; Sonika, G.; Fritzsch, C.; Grieser, S.; Hergemöller, A.; Hetz, B.; Hüsken, N.; Khoukaz, A.; Wessels, J.P.; Khosonthongkee, K.; Kobdaj, C.; Limphirat, A.; Srisawad, P.; Yan, Y.; Barnyakov, M.; Barnyakov, A. Yu.; Beloborodov, K.; Blinov, A.E.; Blinov, V.E.; Bobrovnikov, V.S.; Kononov, S.; Kravchenko, E.A.; Kuyanov, I.A.; Martin, K.; Onuchin, A.P.; Serednyakov, S.; Sokolov, A.; Tikhonov, Y.; Atomssa, E.; Kunne, R.; Marchand, D.; Ramstein, B.; van de Wiele, J.; Wang, Y.; Boca, G.; Costanza, S.; Genova, P.; Montagna, P.; Rotondi, A.; Abramov, V.; Belikov, N.; Bukreeva, S.; Davidenko, A.; Derevschikov, A.; Goncharenko, Y.; Grishin, V.; Kachanov, V.; Kormilitsin, V.; Levin, A.; Melnik, Y.; Minaev, N.; Mochalov, V.; Morozov, D.; Nogach, L.; Poslavskiy, S.; Ryazantsev, A.; Ryzhikov, S.; Semenov, P.; Shein, I.; Uzunian, A.; Vasiliev, A.; Yakutin, A.; Tomasi-Gustafsson, E.; Roy, U.; Yabsley, B.; Belostotski, S.; Gavrilov, G.; Izotov, A.; Manaenkov, S.; Miklukho, O.; Veretennikov, D.; Zhdanov, A.; Makonyi, K.; Preston, M.; Tegner, P.; Wölbing, D.; Bäck, T.; Cederwall, B.; Rai, A.K.; Godre, S.; Calvo, D.; Coli, S.; De Remigis, P.; Filippi, A.; Giraudo, G.; Lusso, S.; Mazza, G.; Mignone, M.; Rivetti, A.; Wheadon, R.; Balestra, F.; Iazzi, F.; Introzzi, R.; Lavagno, A.; Olave, J.; Amoroso, A.; Bussa, M.P.; Busso, L.; De Mori, F.; Destefanis, M.; Fava, L.; Ferrero, L.; Greco, M.; Hu, J.; Lavezzi, L.; Maggiora, M.; Maniscalco, G.; Marcello, S.; Sosio, S.; Spataro, S.; Birsa, R.; Bradamante, F.; Bressan, A.; Martin, A.; Calen, H.; Andersson, W. Ikegami; Johansson, T.; Kupsc, A.; Marciniewski, P.; Papenbrock, M.; Pettersson, J.; Schönning, K.; Wolke, M.; Galnander, B.; Diaz, J.; Chackara, V. Pothodi; Chlopik, A.; Kesik, G.; Melnychuk, D.; Slowinski, B.; Trzcinski, A.; Wojciechowski, M.; Wronka, S.; Zwieglinski, B.; Bühler, P.; Marton, J.; Steinschaden, D.; Suzuki, K.; Widmann, E.; Zmeskal, J.

2016-01-01

The results of simulations for future measurements of electromagnetic form factors at \\PANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision at which the proton form factors can be determined is estimated. The signal channel $\\bar p p \\to e^+ e^-$ is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e. the $\\bar p p \\to \\pi^+ \\pi^-$, is studied. Furthermore, the background versus signal efficiency, statistic and systematic uncertainties on the extracted proton form factors are evaluated using to the two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam condition and detector performances.

Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR

Energy Technology Data Exchange (ETDEWEB)

Singh, B. [Aligarth Muslim Univ., Aligarth (India). Physics Dept.; Erni, W.; Krusche, B. [Basel Univ. (Switzerland); Collaboration: The PANDA Collaboration; and others

2016-10-15

Simulation results for future measurements of electromagnetic proton form factors at PANDA(FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel anti pp → e{sup +}e{sup -} is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e. anti pp → π{sup +}π{sup -}, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance. (orig.)

Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR

International Nuclear Information System (INIS)

Singh, B.

2016-01-01

Simulation results for future measurements of electromagnetic proton form factors at PANDA(FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel anti pp → e + e - is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e. anti pp → π + π - , is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance. (orig.)

On the construction of the Taub-NUT congruence

International Nuclear Information System (INIS)

Hogan, P.A.; Criss, T.

1976-01-01

It is described how the null congruence tangent to the multiple Debever-Penrose direction of the Taub-NUT solution of Einstein's vacuum field equations may be constructed emanating into the future from a timelike world tube having normal cross sections. The curious shapes of the cross sections of the world tube are plotted, using a computer, for critical ranges of the parameter b/R 0 where b is the Taub-NUT parameter and R 0 is the 'radius' of the world tube. It is found that these cross sections can be maintained spatially compact only for some values of b/R 0 . (author)

Negative branes, supergroups and the signature of spacetime

Science.gov (United States)

Dijkgraaf, Robbert; Heidenreich, Ben; Jefferson, Patrick; Vafa, Cumrun

2018-02-01

We study the realization of supergroup gauge theories using negative branes in string theory. We show that negative branes are intimately connected with the possibility of timelike compactification and exotic spacetime signatures previously studied by Hull. Isolated negative branes dynamically generate a change in spacetime signature near their worldvolumes, and are related by string dualities to a smooth M-theory geometry with closed timelike curves. Using negative D3-branes, we show that SU(0| N) supergroup theories are holographically dual to an exotic variant of type IIB string theory on {dS}_{3,2}× {\\overline{S}}^5 , for which the emergent dimensions are timelike. Using branes, mirror symmetry and Nekrasov's instanton calculus, all of which agree, we derive the Seiberg-Witten curve for N=2 SU( N | M ) gauge theories. Together with our exploration of holography and string dualities for negative branes, this suggests that supergroup gauge theories may be non-perturbatively well-defined objects, though several puzzles remain.

Scalar field dark matter: behavior around black holes

Energy Technology Data Exchange (ETDEWEB)

Cruz-Osorio, Alejandro; Guzmán, F. Siddhartha; Lora-Clavijo, Fabio D., E-mail: alejandro@ifm.umich.mx, E-mail: guzman@ifm.umich.mx, E-mail: fadulora@ifm.umich.mx [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Cd. Universitaria, 58040 Morelia, Michoacán (Mexico)

2011-06-01

We present the numerical evolution of a massive test scalar fields around a Schwarzschild space-time. We proceed by using hyperboloidal slices that approach future null infinity, which is the boundary of scalar fields, and also demand the slices to penetrate the event horizon of the black hole. This approach allows the scalar field to be accreted by the black hole and to escape toward future null infinity. We track the evolution of the energy density of the scalar field, which determines the rate at which the scalar field is being diluted. We find polynomial decay of the energy density of the scalar field, and use it to estimate the rate of dilution of the field in time. Our findings imply that the energy density of the scalar field decreases even five orders of magnitude in time scales smaller than a year. This implies that if a supermassive black hole is the Schwarzschild solution, then scalar field dark matter would be diluted extremely fast.

Scalar field dark matter: behavior around black holes

International Nuclear Information System (INIS)

Cruz-Osorio, Alejandro; Guzmán, F. Siddhartha; Lora-Clavijo, Fabio D.

2011-01-01

We present the numerical evolution of a massive test scalar fields around a Schwarzschild space-time. We proceed by using hyperboloidal slices that approach future null infinity, which is the boundary of scalar fields, and also demand the slices to penetrate the event horizon of the black hole. This approach allows the scalar field to be accreted by the black hole and to escape toward future null infinity. We track the evolution of the energy density of the scalar field, which determines the rate at which the scalar field is being diluted. We find polynomial decay of the energy density of the scalar field, and use it to estimate the rate of dilution of the field in time. Our findings imply that the energy density of the scalar field decreases even five orders of magnitude in time scales smaller than a year. This implies that if a supermassive black hole is the Schwarzschild solution, then scalar field dark matter would be diluted extremely fast

Complete conformal classification of the Friedmann–Lemaître–Robertson–Walker solutions with a linear equation of state

Science.gov (United States)

Harada, Tomohiro; Carr, B. J.; Igata, Takahisa

2018-05-01

We completely classify Friedmann–Lemaître–Robertson–Walker solutions with spatial curvature and equation of state , according to their conformal structure, singularities and trapping horizons. We do not assume any energy conditions and allow , thereby going beyond the usual well-known solutions. For each spatial curvature, there is an initial spacelike big-bang singularity for w  >  ‑1/3 and , while there is no big-bang singularity for w  big-bang singularity. For each spatial curvature, there is a final spacelike future big-rip singularity for w  big-rip singularity, then bounces and blows up at a final spacelike future big-rip singularity. For w    ‑1/3, the universe contracts from infinity, then bounces and expands to infinity; for  ‑1  big-bang singularity and contracts to a big-crunch singularity; for w  <  ‑1, it expands from a regular null hypersurface and contracts to another regular null hypersurface.

Recursion Formulae for Obtaining Surfaces with Constant Mean Curvature in R2,1

International Nuclear Information System (INIS)

Tian Yongbo; Nan Zhijie; Tian Chou

2007-01-01

Though the Baecklund transformation on time-like surfaces with constant mean curvature surfaces in R 2,1 has been obtained, it is not easy to obtain corresponding surfaces because the procedure of solving the related integrable system cannot be avoided when the Baecklund transformation is used. For sake of this, in this article, some special work is done to reform the Baecklund transformation to a recursion formula, by which we can construct time-like surfaces with constant mean curvature form known ones just by quadrature procedure.

Optimal time travel in the Gödel universe

Science.gov (United States)

Natário, José

2012-04-01

Using the theory of optimal rocket trajectories in general relativity, recently developed in Henriques and Natário (2011), we present a candidate for the minimum total integrated acceleration closed timelike curve in the Gödel universe, and give evidence for its minimality. The total integrated acceleration of this curve is lower than Malament's conjectured value (Malament 1984), as was already implicit in the work of Manchak (Gen. Relativ. Gravit. 51-60, 2011); however, Malament's conjecture does seem to hold for periodic closed timelike curves.

Straight spinning cosmic strings in Brans-Dicke gravity

Science.gov (United States)

Dos Santos, S. Mittmann; da Silva, J. M. Hoff; Cindra, J. L.

2018-03-01

An exact solution of straight spinning cosmic strings in Brans-Dicke theory of gravitation is presented. The possibility of the existence of closed time-like curves around these cosmic strings is analyzed. Furthermore, the stability about the formation of the topological defect discussed here is checked. It is shown that the existence of a suitable choice for the integration constants in which closed time-like curves are not allowed. We also study the (im)possibility of using the obtained spacetime in the rotational curves problem.

Implications of the stagnation line model for energy input through the dayside magnetopause

International Nuclear Information System (INIS)

Pudovkin, M.I.; Semenov, V.S.; Heyn, M.F.; Biernat, H.K.

1986-01-01

Based on the formation of a stagnation line at the magnetopause the electromagnetic energy transport from the solar wind into the dayside magnetosphere is analyzed. The resulting energy flux is analyzed. The resulting energy flux is proportional to v/sub infinity/B/sub infinity/sin 2 (theta/sub infinity/-phi/sub infinity/), where v/sub infinity/ and B/sub infinity/ are the solar wind speed and magnetic field and theta/sub infinity/-phi/sub s/infinity is the angle between the IMF and the stagnation line projected into the interplanetary space. A stagnation line parallel to the separator gives approximately the sin 4 (theta/sub infinity//2) energy flux dependence of Akasofu's epsilon-index

Compatibility conditions of a singular hypersurface in the relativistic mechanics of the continuous media

International Nuclear Information System (INIS)

Maugin, G.A.

1976-01-01

In this work the compatibility conditions verified by the discontinuities of relativistic fields and of their space-time and time-like derivatives up to be second order are systematically constructed in terms of the local geometry of the wave front (singular hypersurface). A new time-like derivative that generalizes Thomas' delta-derivative of classical continuum mechanics is thus introduced in the relativistic frame. It allows to formulate these conditions in compact forms. It is thus expected that the relativistic analogue of T.Y. Thomas' (1957) classical theory is produced [fr

The supersymmetric configurations of N=2, d=4 supergravity coupled to vector supermultiplets

CERN Document Server

Meessen, P

2006-01-01

We classify all the supersymmetric configurations of ungauged N=2,d=4 supergravity coupled to n vector multiplets and determine under which conditions they are also classical solutions of the equations of motion. The supersymmetric configurations fall into two classes, depending on the timelike or null nature of the Killing vector constructed from Killing spinor bilinears. The timelike class configurations are essentially the ones found by Behrndt, Luest and Sabra, which exhaust this class and are the ones that include supersymmetric black holes. The null class configurations include pp-waves and cosmic strings.

Feasibility studies of time-like proton electromagnetic form factors at overlinePANDA at FAIR

Science.gov (United States)

Singh, B.; Erni, W.; Krusche, B.; Steinacher, M.; Walford, N.; Liu, B.; Liu, H.; Liu, Z.; Shen, X.; Wang, C.; Zhao, J.; Albrecht, M.; Erlen, T.; Fink, M.; Heinsius, F.; Held, T.; Holtmann, T.; Jasper, S.; Keshk, I.; Koch, H.; Kopf, B.; Kuhlmann, M.; Kümmel, M.; Leiber, S.; Mikirtychyants, M.; Musiol, P.; Mustafa, A.; Pelizäus, M.; Pychy, J.; Richter, M.; Schnier, C.; Schröder, T.; Sowa, C.; Steinke, M.; Triffterer, T.; Wiedner, U.; Ball, M.; Beck, R.; Hammann, C.; Ketzer, B.; Kube, M.; Mahlberg, P.; Rossbach, M.; Schmidt, C.; Schmitz, R.; Thoma, U.; Urban, M.; Walther, D.; Wendel, C.; Wilson, A.; Bianconi, A.; Bragadireanu, M.; Caprini, M.; Pantea, D.; Patel, B.; Czyzycki, W.; Domagala, M.; Filo, G.; Jaworowski, J.; Krawczyk, M.; Lisowski, F.; Lisowski, E.; Michałek, M.; Poznański, P.; Płażek, J.; Korcyl, K.; Kozela, A.; Kulessa, P.; Lebiedowicz, P.; Pysz, K.; Schäfer, W.; Szczurek, A.; Fiutowski, T.; Idzik, M.; Mindur, B.; Przyborowski, D.; Swientek, K.; Biernat, J.; Kamys, B.; Kistryn, S.; Korcyl, G.; Krzemien, W.; Magiera, A.; Moskal, P.; Pyszniak, A.; Rudy, Z.; Salabura, P.; Smyrski, J.; Strzempek, P.; Wronska, A.; Augustin, I.; Böhm, R.; Lehmann, I.; Nicmorus Marinescu, D.; Schmitt, L.; Varentsov, V.; Al-Turany, M.; Belias, A.; Deppe, H.; Dzhygadlo, R.; Ehret, A.; Flemming, H.; Gerhardt, A.; Götzen, K.; Gromliuk, A.; Gruber, L.; Karabowicz, R.; Kliemt, R.; Krebs, M.; Kurilla, U.; Lehmann, D.; Löchner, S.; Lühning, J.; Lynen, U.; Orth, H.; Patsyuk, M.; Peters, K.; Saito, T.; Schepers, G.; Schmidt, C. J.; Schwarz, C.; Schwiening, J.; Täschner, A.; Traxler, M.; Ugur, C.; Voss, B.; Wieczorek, P.; Wilms, A.; Zühlsdorf, M.; Abazov, V.; Alexeev, G.; Arefiev, V. A.; Astakhov, V.; Barabanov, M. Yu.; Batyunya, B. V.; Davydov, Y.; Dodokhov, V. Kh.; Efremov, A.; Fechtchenko, A.; Fedunov, A. G.; Galoyan, A.; Grigoryan, S.; Koshurnikov, E. K.; Lobanov, Y. Yu.; Lobanov, V. I.; Makarov, A. F.; Malinina, L. V.; Malyshev, V.; Olshevskiy, A. G.; Perevalova, E.; Piskun, A. A.; Pocheptsov, T.; Pontecorvo, G.; Rodionov, V.; Rogov, Y.; Salmin, R.; Samartsev, A.; Sapozhnikov, M. G.; Shabratova, G.; Skachkov, N. B.; Skachkova, A. N.; Strokovsky, E. A.; Suleimanov, M.; Teshev, R.; Tokmenin, V.; Uzhinsky, V.; Vodopianov, A.; Zaporozhets, S. A.; Zhuravlev, N. I.; Zorin, A. G.; Branford, D.; Glazier, D.; Watts, D.; Böhm, M.; Britting, A.; Eyrich, W.; Lehmann, A.; Pfaffinger, M.; Uhlig, F.; Dobbs, S.; Seth, K.; Tomaradze, A.; Xiao, T.; Bettoni, D.; Carassiti, V.; Cotta Ramusino, A.; Dalpiaz, P.; Drago, A.; Fioravanti, E.; Garzia, I.; Savrie, M.; Akishina, V.; Kisel, I.; Kozlov, G.; Pugach, M.; Zyzak, M.; Gianotti, P.; Guaraldo, C.; Lucherini, V.; Bersani, A.; Bracco, G.; Macri, M.; Parodi, R. F.; Biguenko, K.; Brinkmann, K.; Di Pietro, V.; Diehl, S.; Dormenev, V.; Drexler, P.; Düren, M.; Etzelmüller, E.; Galuska, M.; Gutz, E.; Hahn, C.; Hayrapetyan, A.; Kesselkaul, M.; Kühn, W.; Kuske, T.; Lange, J. S.; Liang, Y.; Metag, V.; Nanova, M.; Nazarenko, S.; Novotny, R.; Quagli, T.; Reiter, S.; Rieke, J.; Rosenbaum, C.; Schmidt, M.; Schnell, R.; Stenzel, H.; Thöring, U.; Ullrich, M.; Wagner, M. N.; Wasem, T.; Wohlfahrt, B.; Zaunick, H.; Ireland, D.; Rosner, G.; Seitz, B.; Deepak, P. N.; Kulkarni, A.; Apostolou, A.; Babai, M.; Kavatsyuk, M.; Lemmens, P. J.; Lindemulder, M.; Loehner, H.; Messchendorp, J.; Schakel, P.; Smit, H.; Tiemens, M.; van der Weele, J. C.; Veenstra, R.; Vejdani, S.; Dutta, K.; Kalita, K.; Kumar, A.; Roy, A.; Sohlbach, H.; Bai, M.; Bianchi, L.; Büscher, M.; Cao, L.; Cebulla, A.; Dosdall, R.; Gillitzer, A.; Goldenbaum, F.; Grunwald, D.; Herten, A.; Hu, Q.; Kemmerling, G.; Kleines, H.; Lehrach, A.; Nellen, R.; Ohm, H.; Orfanitski, S.; Prasuhn, D.; Prencipe, E.; Pütz, J.; Ritman, J.; Schadmand, S.; Sefzick, T.; Serdyuk, V.; Sterzenbach, G.; Stockmanns, T.; Wintz, P.; Wüstner, P.; Xu, H.; Zambanini, A.; Li, S.; Li, Z.; Sun, Z.; Xu, H.; Rigato, V.; Isaksson, L.; Achenbach, P.; Corell, O.; Denig, A.; Distler, M.; Hoek, M.; Karavdina, A.; Lauth, W.; Liu, Z.; Merkel, H.; Müller, U.; Pochodzalla, J.; Sanchez, S.; Schlimme, S.; Sfienti, C.; Thiel, M.; Ahmadi, H.; Ahmed, S.; Bleser, S.; Capozza, L.; Cardinali, M.; Dbeyssi, A.; Deiseroth, M.; Feldbauer, F.; Fritsch, M.; Fröhlich, B.; Jasinski, P.; Kang, D.; Khaneft, D.; Klasen, R.; Leithoff, H. H.; Lin, D.; Maas, F.; Maldaner, S.; Martínez, M.; Michel, M.; Mora Espí, M. C.; Morales Morales, C.; Motzko, C.; Nerling, F.; Noll, O.; Pflüger, S.; Pitka, A.; Rodríguez Piñeiro, D.; Sanchez-Lorente, A.; Steinen, M.; Valente, R.; Weber, T.; Zambrana, M.; Zimmermann, I.; Fedorov, A.; Korjik, M.; Missevitch, O.; Boukharov, A.; Malyshev, O.; Marishev, I.; Balanutsa, V.; Balanutsa, P.; Chernetsky, V.; Demekhin, A.; Dolgolenko, A.; Fedorets, P.; Gerasimov, A.; Goryachev, V.; Chandratre, V.; Datar, V.; Dutta, D.; Jha, V.; Kumawat, H.; Mohanty, A. K.; Parmar, A.; Roy, B.; Sonika, G.; Fritzsch, C.; Grieser, S.; Hergemöller, A.; Hetz, B.; Hüsken, N.; Khoukaz, A.; Wessels, J. P.; Khosonthongkee, K.; Kobdaj, C.; Limphirat, A.; Srisawad, P.; Yan, Y.; Barnyakov, M.; Barnyakov, A. Yu.; Beloborodov, K.; Blinov, A. E.; Blinov, V. E.; Bobrovnikov, V. S.; Kononov, S.; Kravchenko, E. A.; Kuyanov, I. A.; Martin, K.; Onuchin, A. P.; Serednyakov, S.; Sokolov, A.; Tikhonov, Y.; Atomssa, E.; Kunne, R.; Marchand, D.; Ramstein, B.; van de Wiele, J.; Wang, Y.; Boca, G.; Costanza, S.; Genova, P.; Montagna, P.; Rotondi, A.; Abramov, V.; Belikov, N.; Bukreeva, S.; Davidenko, A.; Derevschikov, A.; Goncharenko, Y.; Grishin, V.; Kachanov, V.; Kormilitsin, V.; Levin, A.; Melnik, Y.; Minaev, N.; Mochalov, V.; Morozov, D.; Nogach, L.; Poslavskiy, S.; Ryazantsev, A.; Ryzhikov, S.; Semenov, P.; Shein, I.; Uzunian, A.; Vasiliev, A.; Yakutin, A.; Tomasi-Gustafsson, E.; Roy, U.; Yabsley, B.; Belostotski, S.; Gavrilov, G.; Izotov, A.; Manaenkov, S.; Miklukho, O.; Veretennikov, D.; Zhdanov, A.; Makonyi, K.; Preston, M.; Tegner, P.; Wölbing, D.; Bäck, T.; Cederwall, B.; Rai, A. K.; Godre, S.; Calvo, D.; Coli, S.; De Remigis, P.; Filippi, A.; Giraudo, G.; Lusso, S.; Mazza, G.; Mignone, M.; Rivetti, A.; Wheadon, R.; Balestra, F.; Iazzi, F.; Introzzi, R.; Lavagno, A.; Olave, J.; Amoroso, A.; Bussa, M. P.; Busso, L.; De Mori, F.; Destefanis, M.; Fava, L.; Ferrero, L.; Greco, M.; Hu, J.; Lavezzi, L.; Maggiora, M.; Maniscalco, G.; Marcello, S.; Sosio, S.; Spataro, S.; Birsa, R.; Bradamante, F.; Bressan, A.; Martin, A.; Calen, H.; Ikegami Andersson, W.; Johansson, T.; Kupsc, A.; Marciniewski, P.; Papenbrock, M.; Pettersson, J.; Schönning, K.; Wolke, M.; Galnander, B.; Diaz, J.; Pothodi Chackara, V.; Chlopik, A.; Kesik, G.; Melnychuk, D.; Slowinski, B.; Trzcinski, A.; Wojciechowski, M.; Wronka, S.; Zwieglinski, B.; Bühler, P.; Marton, J.; Steinschaden, D.; Suzuki, K.; Widmann, E.; Zmeskal, J.

2016-10-01

Simulation results for future measurements of electromagnetic proton form factors at overlinePANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel bar{p}p→ e+e- is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e. bar{p}p→ π+π-, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance.

Regular black holes: electrically charged solutions, Reissner-Nordstroem outside a De Sitter core

Energy Technology Data Exchange (ETDEWEB)

Lemos, Jose P.S. [Universidade Tecnica de Lisboa (CENTRA/IST/UTL) (Portugal). Instituto Superior Tecnico. Centro Multidisciplinar de Astrofisica; Zanchin, Vilson T. [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Centro de Ciencias Naturais e Humanas

2011-07-01

Full text: The understanding of the inside of a black hole is of crucial importance in order to have the correct picture of a black hole as a whole. The singularities that lurk inside of the usual black hole solutions are things to avoid. Their substitution by a regular part is of great interest, the process generating regular black holes. In the present work regular black hole solutions are found within general relativity coupled to Maxwell's electromagnetism and charged matter. We show that there are objects which correspond to regular charged black holes, whose interior region is de Sitter, whose exterior region is Reissner-Nordstroem, and the boundary between both regions is made of an electrically charged spherically symmetric coat. There are several solutions: the regular nonextremal black holes with a null matter boundary, the regular nonextremal black holes with a timelike matter boundary, the regular extremal black holes with a timelike matter boundary, and the regular overcharged stars with a timelike matter boundary. The main physical and geometrical properties of such charged regular solutions are analyzed. (author)

Anholonomic Cauchy problem in general relativity

International Nuclear Information System (INIS)

Stachel, J.

1980-01-01

The Lie derivative approach to the Cauchy problem in general relativity is applied to the evolution along an arbitrary timelike vector field for the case where the dynamical degrees of freedom are chosen as the (generally anholonomic) metric of the hypersurface elements orthogonal to the vector field. Generalizations of the shear, rotation, and acceleration are given for a nonunit timelike vector field, and applied to the three-plus-one breakup of the Riemann tensor into components parallel and orthogonal to the vector field, resulting in the anholonomic Gauss--Codazzi equations. A similar breakup of the Einstein field equations results in the form of the constraint and evolution equations for the anholonomic case. The results are applied to the case of a space--time with a timelike Killing vector field (stationary field) to demonstrate their utility. Other possible applications, such as in the numerical integration of the field equations, are mentioned. Definitions are given of three-index shear, rotation, and acceleration tensors, and their use in a two-plus-two decomposition of the Riemann tensor and field equations is indicated

Futuring for Future Ready Librarians

Science.gov (United States)

Figueroa, Miguel A.

2018-01-01

Futurists and foresight professionals offer several guiding principles for thinking about the future. These principles can help people to think about the future and become more powerful players in shaping the preferred futures they want for themselves and their communities. The principles also fit in well as strategies to support the Future Ready…

BMS in cosmology

International Nuclear Information System (INIS)

Kehagias, A.; Riotto, A.

2016-01-01

Symmetries play an interesting role in cosmology. They are useful in characterizing the cosmological perturbations generated during inflation and lead to consistency relations involving the soft limit of the statistical correlators of large-scale structure dark matter and galaxies overdensities. On the other hand, in observational cosmology the carriers of the information about these large-scale statistical distributions are light rays traveling on null geodesics. Motivated by this simple consideration, we study the structure of null infinity and the associated BMS symmetry in a cosmological setting. For decelerating Friedmann-Robertson-Walker backgrounds, for which future null infinity exists, we find that the BMS transformations which leaves the asymptotic metric invariant to leading order. Contrary to the asymptotic flat case, the BMS transformations in cosmology generate Goldstone modes corresponding to scalar, vector and tensor degrees of freedom which may exist at null infinity and perturb the asymptotic data. Therefore, BMS transformations generate physically inequivalent vacua as they populate the universe at null infinity with these physical degrees of freedom. We also discuss the gravitational memory effect when cosmological expansion is taken into account. In this case, there are extra contribution to the gravitational memory due to the tail of the retarded Green functions which are supported not only on the light-cone, but also in its interior. The gravitational memory effect can be understood also from an asymptotic point of view as a transition among cosmological BMS-related vacua.

BMS in cosmology

Energy Technology Data Exchange (ETDEWEB)

Kehagias, A. [Physics Division, National Technical University of Athens, 15780 Zografou Campus, Athens (Greece); Riotto, A. [Department of Theoretical Physics,24 quai E. Ansermet, CH-1211 Geneva 4 (Switzerland); Center for Astroparticle Physics (CAP),24 quai E. Ansermet, CH-1211 Geneva 4 (Switzerland)

2016-05-25

Symmetries play an interesting role in cosmology. They are useful in characterizing the cosmological perturbations generated during inflation and lead to consistency relations involving the soft limit of the statistical correlators of large-scale structure dark matter and galaxies overdensities. On the other hand, in observational cosmology the carriers of the information about these large-scale statistical distributions are light rays traveling on null geodesics. Motivated by this simple consideration, we study the structure of null infinity and the associated BMS symmetry in a cosmological setting. For decelerating Friedmann-Robertson-Walker backgrounds, for which future null infinity exists, we find that the BMS transformations which leaves the asymptotic metric invariant to leading order. Contrary to the asymptotic flat case, the BMS transformations in cosmology generate Goldstone modes corresponding to scalar, vector and tensor degrees of freedom which may exist at null infinity and perturb the asymptotic data. Therefore, BMS transformations generate physically inequivalent vacua as they populate the universe at null infinity with these physical degrees of freedom. We also discuss the gravitational memory effect when cosmological expansion is taken into account. In this case, there are extra contribution to the gravitational memory due to the tail of the retarded Green functions which are supported not only on the light-cone, but also in its interior. The gravitational memory effect can be understood also from an asymptotic point of view as a transition among cosmological BMS-related vacua.

Singularities in geodesic surface congruence

International Nuclear Information System (INIS)

Cho, Yong Seung; Hong, Soon-Tae

2008-01-01

In the stringy cosmology, we investigate singularities in geodesic surface congruences for the timelike and null strings to yield the Raychaudhuri type equations possessing correction terms associated with the novel features owing to the strings. Assuming the stringy strong energy condition, we have a Hawking-Penrose type inequality equation. If the initial expansion is negative so that the congruence is converging, we show that the expansion must pass through the singularity within a proper time. We observe that the stringy strong energy conditions of both the timelike and null string congruences produce the same inequality equation.

Spinorial Characterizations of Surfaces into 3-dimensional Pseudo-Riemannian Space Forms

International Nuclear Information System (INIS)

Lawn, Marie-Amélie; Roth, Julien

2011-01-01

We give a spinorial characterization of isometrically immersed surfaces of arbitrary signature into 3-dimensional pseudo-Riemannian space forms. This generalizes a recent work of the first author for spacelike immersed Lorentzian surfaces in ℝ 2,1 to other Lorentzian space forms. We also characterize immersions of Riemannian surfaces in these spaces. From this we can deduce analogous results for timelike immersions of Lorentzian surfaces in space forms of corresponding signature, as well as for spacelike and timelike immersions of surfaces of signature (0, 2), hence achieving a complete spinorial description for this class of pseudo-Riemannian immersions.

Simulating the dynamics of relativistic stars via a light-cone approach

International Nuclear Information System (INIS)

Siebel, Florian; Mueller, Ewald; Font, Jose A.; Papadopoulos, Philippos

2002-01-01

We present new numerical algorithms for the coupled Einstein-perfect-fluid system in axisymmetry. Our framework uses a foliation based on a family of light cones, emanating from a regular center, and terminating at future null infinity. This coordinate system is well adapted to the study of the dynamical spacetimes associated with isolated relativistic compact objects such as neutron stars. In particular, the approach allows the unambiguous extraction of gravitational waves at future null infinity and avoids spurious outer boundary reflections. The code can accurately maintain long-term stability of polytropic equilibrium models of relativistic stars. We demonstrate global energy conservation in a strongly perturbed neutron star spacetime, for which the total energy radiated away by gravitational waves corresponds to a significant fraction of the Bondi mass. As a first application we present results in the study of pulsations of axisymmetric relativistic stars, extracting the frequencies of the different fluid modes in fully relativistic evolutions of the Einstein-perfect-fluid system and making a first comparison between the gravitational news function and the predicted wave using the approximations of the quadrupole formula

Are asymptotically non-free theories with vanishing anomalous dimension really excluded

International Nuclear Information System (INIS)

Geicke, J.

1979-01-01

In a fictitious ultraviolet fixed point gsub(infinity) (in gPHI 4 /4factorial theory) with asymptotic behaviour the two-point function differs from the free two-point function at p 2 = 0 if rhosub(infinity)-sigmasub(infinity)>= 1. Under this aspect a recent result predicting a fixed point gsub(infinity) > 0 with γgsub(infinity) = 0 is no longer contradictory. (Auth.)

Local Hawking temperature for dynamical black holes

International Nuclear Information System (INIS)

Hayward, S A; Criscienzo, R Di; Nadalini, M; Vanzo, L; Zerbini, S

2009-01-01

A local Hawking temperature is derived for any future outer trapping horizon in spherical symmetry, using a Hamilton-Jacobi variant of the Parikh-Wilczek tunneling method. It is given by a dynamical surface gravity as defined geometrically. The operational meaning of the temperature is that Kodama observers just outside the horizon measure an invariantly redshifted temperature, diverging at the horizon itself. In static, asymptotically flat cases, the Hawking temperature as usually defined by the Killing vector agrees in standard cases, but generally differs by a relative redshift factor between the horizon and infinity, this being the temperature measured by static observers at infinity. Likewise, the geometrical surface gravity reduces to the Newtonian surface gravity in the Newtonian limit, while the Killing definition instead reflects measurements at infinity. This may resolve a long-standing puzzle concerning the Hawking temperature for the extremal limit of the charged stringy black hole, namely that it is the local temperature which vanishes. In general, this confirms the quasi-stationary picture of black-hole evaporation in early stages. However, the geometrical surface gravity is generally not the surface gravity of a static black hole with the same parameters. (fast track communication)

Poisson's theorem and integrals of KdV equation

International Nuclear Information System (INIS)

Tasso, H.

1978-01-01

Using Poisson's theorem it is proved that if F = integral sub(-infinity)sup(+infinity) T(u,usub(x),...usub(n,t))dx is an invariant functional of KdV equation, then integral sub(-infinity)sup(+infinity) delta F/delta u dx integral sub(-infinity)sup(+infinity) delta T/delta u dx is also an invariant functional. In the case of a polynomial T, one finds in a simple way the known recursion ΔTr/Δu = Tsub(r-1). This note gives an example of the usefulness of Poisson's theorem. (author)

FutureCoast: "Listen to your futures"

Science.gov (United States)

Pfirman, S. L.; Eklund, K.; Thacher, S.; Orlove, B. S.; Diane Stovall-Soto, G.; Brunacini, J.; Hernandez, T.

2014-12-01

Two science-arts approaches are emerging as effective means to convey "futurethinking" to learners: systems gaming and experiential futures. FutureCoast exemplifies the latter: by engaging participants with voicemails supposedly leaking from the cloud of possible futures, the storymaking game frames the complexities of climate science in relatable contexts. Because participants make the voicemails themselves, FutureCoast opens up creative ways for people to think about possibly climate-changed futures and personal ways to talk about them. FutureCoast is a project of the PoLAR Partnership with a target audience of informal adult learners primarily reached via mobile devices and online platforms. Scientists increasingly use scenarios and storylines as ways to explore the implications of environmental change and societal choices. Stories help people make connections across experiences and disciplines and link large-scale events to personal consequences. By making the future seem real today, FutureCoast's framework helps people visualize and plan for future climate changes. The voicemails contributed to FutureCoast are spread through the game's intended timeframe (2020 through 2065). Based on initial content analysis of voicemail text, common themes include ecosystems and landscapes, weather, technology, societal issues, governance and policy. Other issues somewhat less frequently discussed include security, food, industry and business, health, energy, infrastructure, water, economy, and migration. Further voicemail analysis is examining: temporal dimensions (salient time frames, short vs. long term issues, intergenerational, etc.), content (adaptation vs. mitigation, challenges vs. opportunities, etc.), and emotion (hopeful, resigned, etc. and overall emotional context). FutureCoast also engaged audiences through facilitated in-person experiences, geocaching events, and social media (Tumblr, Twitter, Facebook, YouTube). Analysis of the project suggests story

The effect of sources on horizons that may develop when plane gravitational waves collide

International Nuclear Information System (INIS)

Chandrasekhar, Subrahmanyan; Xanthopoulos, B.C.

1987-01-01

Colliding plane gravitational waves that lead to the development of a horizon and a subsequent time-like singularity are coupled with an electromagnetic field, a perfect fluid, and null dust (consisting of massless particles). The coupling of the gravitational waves with an electromagnetic field does not affect, in any essential way, the development of the horizon or the time-like singularity if the polarizations of the colliding gravitational waves are not parallel. If the polarizations are parallel, the space-like singularity which occurs in the vacuum is transformed into a horizon followed by a three-dimensional time-like singularity by the merest presence of the electromagnetic field. The coupling of the gravitational waves with a perfect fluid and null dust affect the development of horizons and singularities in radically different ways: the perfect fluid affects the development decisively in all cases but qualitatively in the same way, while null dust prevents the development of horizons and allows only the development of space-like singularities. The contrasting behaviours of a perfect fluid and of null dust in the framework of general relativity is compared with the behaviours one may expect, under similar circumstances, in the framework of special relativity. (author)

Bell's inequalities from the field concept in general relativity

International Nuclear Information System (INIS)

Sachs, M.

1980-01-01

A nonlinear field theory of matter, based axiomatically on general relativity, has an asymptotic, low-energy limit that predicts the outcome of experimental tests of Bell's inequalities. The inequalities should follow if spin-correlated, spin-1/2 particles, observed in coincidence, were a spacelike distance apart; they should be violated if they were separated by timelike distances. The experiment at timelike separations, for scattered protons observed in coincidence, was carried out by Lahemi-Rachti and Mittig and, thus far, agrees with this theory. Extension of the low-energy pp scattering experiment to observations at spacelike distances is suggested, with the prediction that agreement should be obtained with Bell's inequalities there. (author)

Scaling violations beyond the leading order

CERN Document Server

Petronzio, R

1981-01-01

The authors are concerned with the explicit construction of a method which generalizes beyond leading order the simple probabilistic interpretation of leading scaling violations. The results obtained in this language allow to predict the evolution with the variation of external invariants not only of 'space-like' processes, where the off- shell partons starting the hard interaction have space-like four momenta, like in the case of deep inelastic scattering or Drell-Yan, but also of 'time-like' processes, like the one-particle inclusive e /sup +/e/sup -/ annihilation, where the partons acting in the fragmentation functions have 'time-like' off-shell invariant masses. (9 refs).

An obstacle to building a time machine

International Nuclear Information System (INIS)

Carroll, S.M.; Farhi, E.; Guth, A.H.

1992-01-01

Gott has shown that a spacetime with two infinite parallel cosmic strings passing each other with sufficient velocity contains closed timelike curves. We discuss an attempt to build such a time machine. Using the energy-momentum conservation laws in the equivalent (2+1)-dimensional theory, we explicitly construct the spacetime representing the decay of one gravitating particle into two. We find that there is never enough mass in an open universe to build the time machine from the products of decays of stationary particles. More generally, the Gott time machine cannot exist in any open (2+1)-dimensional universe for which the total momentum is timelike

The momentum degree of freedom of elementary particles and the gravitation

International Nuclear Information System (INIS)

Tati, Takao.

1978-01-01

A universal time-like vector has been introduced into the momentum space of elementary particles, in a quantum field theory with a finite degree of freedom, in order to specify the Lorentz-system in which the cutoff function of momentum is given. In this paper, the relationship between quantum field theory and general relativity is considered and it is argued that, when the effect of gravitation on the momentum degree of freedom is taken into account, the universal time-like vector depends on the position of macroscopic space-time and can be considered, in a cosmological model, to coincide, on an average, with the Weyl's cosmic time. (auth.)

Fermat principles in general relativity and the existence of light rays on Lorentzian manifolds

International Nuclear Information System (INIS)

Fortunato, D.; Masiello, A.

1995-01-01

In this paper we review some results on the existence and multiplicity of null geodesics (light rays) joining a point with a timelike curve on a Lorentzian manifold. Moreover a Morse Theory for such geodesics is presented. A variational principle, which is a variant of the classical Fermat principle in optics, allows to characterize the null geodesics joining a point with a timelike curve as the critical points of a functional on an infinite dimensional manifold. Global variational methods are used to get the existence results and Morse Theory. Such results cover a class of Lorentzian manifolds including Schwarzschild, Reissner-Nordstroem and Kerr space-time. (author)

Deflection of massive neutrinos by gravitational fields

International Nuclear Information System (INIS)

Fargion, D.

1981-01-01

The curvature undergone by massive neutrino trajectories, passing by a mass M at a distance b from the center of a body, is examined. Calculations led to the following angle of deflection: δ rho = 2GM/b#betta# 2 sub(infinity)C 2 (1 + #betta# 2 sub(infinity)), where #betta#sub(infinity) is the dimensionless velocity of the particle at infinity. The ultrarelativistic limit (#betta#sub(infinity) = 1) coincides with the usual massless deflection. Physical consequences are considered. (author)

Futures Brokerages Face uncertain Future

Institute of Scientific and Technical Information of China (English)

WANG PEI

2006-01-01

@@ 2005 was a quiet year for China's futures market.After four new trading products, including cotton, fuel oil and corn, were launched on the market in 2004, the development of the market seemed to stagnate. The trade value of the futures market totaled 13.4 trillion yuan (US$ 1.67 trillion) in 2005, down 8.5 percent year-on-year. Although the decrease is quite small and the trade value was still the second highest in the market's history, the majority of futures brokerage firms were running in the red. In some areas, up to 80 percent of futures companies made losses.

On the general theory of quantized fields

International Nuclear Information System (INIS)

Fredenhagen, K.

1991-10-01

In my lecture I describe the present stage of the general theory of quantized fields on the example of 5 subjects. They are ordered in the direction from large to small distances. The first one is the by now classical problem of the structure of superselection sectors. It involves the behavior of the theory at spacelike infinity and is directly connected with particle statistics and internal symmetries. It has become popular in recent years by the discovery of a lot of nontrivial models in 2d conformal-field theory, by connections to integrable models and critical behavior in statistical mechanics and by the relations to the Jones' theory of subfactors in von Neumann algebras and to the corresponding geometrical objects (braids, knots, 3d manifolds, ...). At large timelike distances the by far most important feature of quantum field theory is the particle structure. This will be the second subject of my lecture. It follows the technically most involved part which is concerned with the behavior at finite distances. Two aspets, nuclearity which emphasizes the finite density of states in phase space, and the modular structure which relies on the infinite number of degrees of freedom present even locally, and their mutual relations will be treated. The next point, involving the structure at infinitesimal distances, is the connection between the Haag-Kastler framework of algebras of local and the framework of Wightman fields. Finally, problems in approaches to quantum gravity will be discussed, as far as they are accessible by the methods of the general theory of quantized fields. (orig.)

Quasilocal energy and conserved charges derived from the gravitational action

International Nuclear Information System (INIS)

Brown, J.D.; York, J.W. Jr.

1993-01-01

The quasilocal energy of gravitational and matter fields in a spatially bounded region is obtained by employing a Hamilton-Jacobi analysis of the action functional. First, a surface stress-energy-momentum tensor is defined by the functional derivative of the action with respect to the three-metric on 3 B, the history of the system's boundary. Energy surface density, momentum surface density, and spatial stress are defined by projecting the surface stress tensor normally and tangentially to a family of spacelike two-surfaces that foliate 3 B. The integral of the energy surface density over such a two-surface B is the quasilocal energy associated with a spacelike three-surface Σ whose orthogonal intersection with 3 B is the boundary B. The resulting expression for quasilocal energy is given in terms of the total mean curvature of the spatial boundary B as a surface embedded in Σ. The quasilocal energy is also the value of the Hamiltonian that generates unit magnitude proper-time translations on 3 B in the timelike direction orthogonal to B. Conserved charges such as angular momentum are defined using the surface stress tensor and Killing vector fields on 3 B. For spacetimes that are asymptotically flat in spacelike directions, the quasilocal energy and angular momentum defined here agree with the results of Arnowitt, Deser, and Misner in the limit that the boundary tends to spatial infinity. For spherically symmetric spacetimes, it is shown that the quasilocal energy has the correct Newtonian limit, and includes a negative contribution due to gravitational binding

Different glassy states, as indicated by a violation of the generalized Cauchy relation

Energy Technology Data Exchange (ETDEWEB)

Krueger, J K [Laboratoire Europeen de Recherche Universitaire Saarland-Lorraine (LERUSL), Universitaet des Saarlandes, Fakultaet fuer Physik und Elektrotechnik 7.2, Gebaeude 38, D-66041 Saarbruecken (Germany); Britz, T [Laboratoire Europeen de Recherche Universitaire Saarland-Lorraine (LERUSL), Universitaet des Saarlandes, Fakultaet fuer Physik und Elektrotechnik 7.2, Gebaeude 38, D-66041 Saarbruecken (Germany); Coutre, A le [Laboratoire Europeen de Recherche Universitaire Saarland-Lorraine (LERUSL), Universitaet des Saarlandes, Fakultaet fuer Physik und Elektrotechnik 7.2, Gebaeude 38, D-66041 Saarbruecken (Germany); Baller, J [Laboratoire Europeen de Recherche Universitaire Saarland-Lorraine (LERUSL), Universitaet des Saarlandes, Fakultaet fuer Physik und Elektrotechnik 7.2, Gebaeude 38, D-66041 Saarbruecken (Germany); Possart, W [Universitaet des Saarlandes, Fakultaet fuer Chemie, Pharmazie und Werkstoffwissenschaften 8.15, Gebaeude 22, D-66041 Saarbruecken (Germany); Alnot, P [Laboratoire Europeen de Recherche Universitaire Saarland-Lorraine (LERUSL), Universitaet des Saarlandes, Fakultaet fuer Physik und Elektrotechnik 7.2, Gebaeude 38, D-66041 Saarbruecken (Germany); Sanctuary, R [Centre Universitaire de Luxembourg, Departement des Sciences, Laboratoire 1.19, 162a Avenue de la Faiencerie, L-1511, Luxembourg (Luxembourg)

2003-07-01

Using Brillouin spectroscopy as a probe for high-frequency clamped acoustic properties, a shear modulus c{sub 44}{sup {infinity}} can be measured in addition to the longitudinal modulus c{sub 11}{sup {infinity}} already well above the thermal glass transition. On slow cooling of the liquid through the thermal glass transition temperature T{sub g}, both moduli show a kink-like behaviour and the function c{sub 11}{sup {infinity}} = c{sub 11}{sup {infinity}}(c{sub 44}{sup {infinity}}) follows a generalized Cauchy relation (gCR) defined by the linear relation c{sub 11}{sup {infinity}} = 3c{sub 44}{sup {infinity}} + constant, which completely hides the glass transition. In this work we show experimentally that on fast cooling this linear transformation becomes violated within the glassy state, but that thermal ageing drives the elastic coefficients towards the gCR, i.e. towards a unique glassy state.

Multiobjective Control for Multivariable Systems with Mixed-sensitivity Specifications

DEFF Research Database (Denmark)

Stoustrup, Jakob; Niemann, H.H.

1997-01-01

A series of multi objective H-infinity design problems are considered in this paper. The problems are formulated as a number of coupled H-infinity design problems. These H-infinity problems can be formulated as sensitivity problems, complementary sensitivity problems, or control sensitivity...... problems for every output (or input) in the system. It turns out that these multi objective H-infinity design problems, based on a number of different types of sensitivity problems, can be exactly decoupled into k H-infinity sensitivity problems for stable systems, where k is the number of outputs (for...

Photorefraction of eyes: history and future prospects.

Science.gov (United States)

Howland, Howard C

2009-06-01

A brief history of photorefraction, i.e., the refraction of eyes by photography or computer image capture, is given. The method of photorefraction originated from an optical scheme for secret communication across the Berlin wall. This scheme used a lens whose focus about infinity was modulated by a movable reflecting surface. From this device, it was recognized that the vertebrate eye was such a reflector and that its double-pass pointspread could be used to compute its degree of defocus. Subsequently, a second, totally independent invention, more accurately termed "photoretinoscopy," used an eccentric light source and obtained retinoscopic-like images of the reflex in the pupil of the subject's eyes. Photoretinoscopy has become the preferred method of photorefraction and has been instantiated in a wide variety of devices used in vision screening and research. This has been greatly helped by the parallel development of computer and digital camera technology. It seems likely that photorefractive methods will continue to be refined and may eventually become ubiquitous in clinical practice.

Sensitivity Synthesis for MIMO Systems: A Multi Objective H^2 Approach

DEFF Research Database (Denmark)

Stoustrup, Jakob; Niemann, Hans Henrik

1996-01-01

A series of multi objective QTR H-infinity designproblems are considered in this paper. The problems are formulatedas a number of coupled QTR H-infinity design problems. TheseQTR H-infinity problems can be formulated as sensitivityproblems, complementary sensitivity problems, or control...... sensitivityproblems for every output (or input) in the system. It turns out thatthese multi objective QTR H-infinity design problems, based ona number of different types of sensitivity problems, can be exactlydecoupled into k\\QTR H-infinity sensitivity problems for stablesystems, where k is the number of outputs (for...... unstable systems,independent stabilization is required). Further, it is shown how to usesimilar techniques to incorporate simultaneous specifications for differentcontrol objectives such as QTR H-infinity, etc., for the sensitivities....

Supersymmetric solutions of N =(1 ,1 ) general massive supergravity

Science.gov (United States)

Deger, N. S.; Nazari, Z.; Sarıoǧlu, Ö.

2018-05-01

We construct supersymmetric solutions of three-dimensional N =(1 ,1 ) general massive supergravity (GMG). Solutions with a null Killing vector are, in general, pp-waves. We identify those that appear at critical points of the model, some of which do not exist in N =(1 ,1 ) new massive supergravity (NMG). In the timelike case, we find that many solutions are common with NMG, but there is a new class that is genuine to GMG, two members of which are stationary Lifshitz and timelike squashed AdS spacetimes. We also show that in addition to the fully supersymmetric AdS vacuum, there is a second AdS background with a nonzero vector field that preserves 1 /4 supersymmetry.

Negative-mass lagging cores of the big bang

International Nuclear Information System (INIS)

Miller, B.D.

1976-01-01

Examples are given of spherically symmetric cosmological models containing space-sections with the following properties: at large values of the geometrically defined coordinate R, the mass is positive, while at small values of R, the mass is negative. The negative-mass region of spacetime has local properties similar to those of the negative-mass Schwarzschild solution. The big bang in these models is partially spacelike and partially timelike, so the spacetimes do not obey the strong form of the cosmic censorship hypothesis. The timelike, negative-mass segments of the big bang are unlimited sources of electromagnetic and gravitational radiation, and as such may be attractive as ''lagging core'' models of highly energetic astrophysical phenomena

Negative-mass lagging cores of the big bang

Energy Technology Data Exchange (ETDEWEB)

Miller, B.D.

1976-09-01

Examples are given of spherically symmetric cosmological models containing space-sections with the following properties: at large values of the geometrically defined coordinate R, the mass is positive, while at small values of R, the mass is negative. The negative-mass region of spacetime has local properties similar to those of the negative-mass Schwarzschild solution. The big bang in these models is partially spacelike and partially timelike, so the spacetimes do not obey the strong form of the cosmic censorship hypothesis. The timelike, negative-mass segments of the big bang are unlimited sources of electromagnetic and gravitational radiation, and as such may be attractive as ''lagging core'' models of highly energetic astrophysical phenomena. (AIP)

Einstein-Podolsky-Rosen constraints on quantum action at a distance: the Sutherland paradox

International Nuclear Information System (INIS)

Cufaro-Petroni, N.; Dewdney, C.; Holland, P.R.; Kyprianidis, A.; Vigier, J.P.

1987-01-01

Assuming that future experiments confirm Aspect's discovery of nonlocal interactions between quantum pairs of correlated particles, the authors analyze the constraints imposed by the EPR reasoning on the said interactions. It is then shown that the nonlocal relativistic quantum potential approach plainly satisfies the Einstein causality criteria as well as the energy-momentum conservation in individual microprocesses. Furthermore, this approach bypasses a new causal paradox for timelike separated EPR measurements deduced by Sutherland in the frame of an approach by means of space-time zigzags with advanced potentials. It is finally demonstrated that this inherent quantum causal direct interaction established permanent EPR correlations which are always restricted to spacelike separations and are instantaneous only in the center-of-mass rest frame of the two-particle system

An Infinity of Voices

DEFF Research Database (Denmark)

Lübcke, Poul

Artiklen sammenligner indledningen til Frygt og Bæven med den opbyggelige tale, "Bekræftelsen i det indvortes Menneske" og viser, hvorledes det paradokse trosbegreb i Frygt og Bæven står i skarp modsætning med det nærmest naive trosbegreb i den opbyggelige tale. Der argumenteres for, at de to tro...

A confrontation with infinity

International Nuclear Information System (INIS)

Hooft, G. 't

2000-01-01

The author's contribution to the proof of renormalizability of gauge theories is highlighted. Attention is paid to weak interactions, renormalization group, standard model, and superstring theory. The lecture is supplemented with a short author's autobiography. (P.A.)

Variational principle for gravity with null and non-null boundaries: a unified boundary counter-term

Energy Technology Data Exchange (ETDEWEB)

Parattu, Krishnamohan; Chakraborty, Sumanta; Padmanabhan, T. [IUCAA, Post Bag 4, Pune (India)

2016-03-15

It is common knowledge that the Einstein-Hilbert action does not furnish a well-posed variational principle. The usual solution to this problem is to add an extra boundary term to the action, called a counter-term, so that the variational principle becomes well-posed. When the boundary is spacelike or timelike, the Gibbons-Hawking-York counter-term is the most widely used. For null boundaries, we had proposed a counter-term in a previous paper. In this paper, we extend the previous analysis and propose a counter-term that can be used to eliminate variations of the ''off-the-surface'' derivatives of the metric on any boundary, regardless of its spacelike, timelike or null nature. (orig.)

No-Hypersignaling Principle

Science.gov (United States)

Dall'Arno, Michele; Brandsen, Sarah; Tosini, Alessandro; Buscemi, Francesco; Vedral, Vlatko

2017-07-01

A paramount topic in quantum foundations, rooted in the study of the Einstein-Podolsky-Rosen (EPR) paradox and Bell inequalities, is that of characterizing quantum theory in terms of the spacelike correlations it allows. Here, we show that to focus only on spacelike correlations is not enough: we explicitly construct a toy model theory that, while not contradicting classical and quantum theories at the level of spacelike correlations, still displays an anomalous behavior in its timelike correlations. We call this anomaly, quantified in terms of a specific communication game, the "hypersignaling" phenomena. We hence conclude that the "principle of quantumness," if it exists, cannot be found in spacelike correlations alone: nontrivial constraints need to be imposed also on timelike correlations, in order to exclude hypersignaling theories.

Novel needle guide reduces time to perform ultrasound-guided femoral nerve catheter placement: A randomised controlled trial.

Science.gov (United States)

Turan, Alparslan; Babazade, Rovnat; Elsharkawy, Hesham; Esa, Wael Ali Sakr; Maheshwari, Kamal; Farag, Ehab; Zimmerman, Nicole M; Soliman, Loran Mounir; Sessler, Daniel I

2017-03-01

Ultrasound-guided nerve blocks have become the standard when performing regional nerve blocks in anaesthesia. Infiniti Plus (CIVCO Medical Solutions, Kalona, Iowa, USA) is a needle guide that has been recently developed to help clinicians in performing ultrasound-guided nerve blocks. We tested the hypothesis that femoral nerve catheter placement carried out with the Infiniti Plus needle guide will be quicker to perform than without the Infiniti Plus. Secondary aims were to assess whether the Infiniti Plus needle guide decreased the number of block attempts and also whether it improved needle visibility. A randomised, controlled trial. Cleveland Clinic, Cleveland, Ohio, USA. We enrolled adult patients having elective total knee arthroplasty with a femoral nerve block and femoral nerve catheter. Patients, who were pregnant or those who had preexisting neuropathy involving the surgical limb, coagulopathy, infection at the block site or allergy to local anaesthetics were excluded. Patients were randomised into two groups to receive the ultrasound-guided femoral nerve catheter placement with or without the Infiniti Plus needle guide. The time taken to place the femoral nerve catheter, the number of attempts, the success rate and needle visibility were recorded. We used an overall α of 0.05 for both the primary and secondary analyses; the secondary analyses were Bonferroni corrected to control for multiple comparisons. The median (interquartile range Q1 to Q3) time to perform the femoral nerve catheter placement was 118 (100 to 150) s with Infiniti Plus and 177 (130 to 236) s without Infiniti Plus. Infiniti Plus significantly reduced the time spent performing femoral nerve catheterisation, with estimated ratio of means [(95% confidence interval), P value] of 0.67 [(0.60 to 0.75), P Infiniti Plus compared with no Infiniti Plus. However, Infiniti Plus had no effect on the odds of a successful femoral nerve catheter placement, number of attempts or percentage of perfect

Aristotelian Finitism

NARCIS (Netherlands)

Nawar, Tamer

2015-01-01

It is widely known that Aristotle rules out the existence of actual infinities but allows for potential infinities. However, precisely why Aristotle should deny the existence of actual infinities remains somewhat obscure and has received relatively little attention in the secondary literature. In

Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 1-(3-hydroxypropyl)pyridinium bis(trifluoromethylsulfonyl)-amide

Energy Technology Data Exchange (ETDEWEB)

Marciniak, Andrzej, E-mail: a.marciniak@ch.pw.edu.pl [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)

2011-10-15

Highlights: > The {gamma}{sub 13}{sup {infinity}} and KL for 46 solutes in the ionic liquid [N-C3OHPY][NTf2] were determined by GLC at different temperatures. > The partial molar excess Gibbs energies {Delta}G{sub 1}{sup E,{infinity}}, enthalpies {Delta}H{sub 1}{sup E,{infinity}} and entropies {Delta}S{sub 1}{sup E,{infinity}} at infinite dilution were calculated. > The selectivities for aliphatics/aromatics hydrocarbons separation problem were calculated and compared to other ILs, NMP and sulfolane. > The selectivities for selected compounds which form azeotropic mixtures were calculated. - Abstract: The activity coefficients at infinite dilution, {gamma}{sub 13}{sup {infinity}} and gas-liquid partition coefficients, K{sub L} for 46 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, acetic acid, and water in the ionic liquid 1-(3-hydroxypropyl)pyridinium bis(trifluoromethylsulfonyl)-amide were determined by gas-liquid chromatography at the temperatures from (308.15 to 378.15) K. The partial molar excess Gibbs free energies {Delta}G{sub 1}{sup E,{infinity}}, enthalpies {Delta}H{sub 1}{sup E,{infinity}} and entropies {Delta}S{sub 1}{sup E,{infinity}} at infinite dilution were calculated from the experimental {gamma}{sub 13}{sup {infinity}} values obtained over the temperature range. The selectivities for aliphatic/aromatic hydrocarbons separation problem were calculated from the {gamma}{sub 13}{sup {infinity}} and compared to the literature values for other ionic liquids based on bis(trifluoromethylsulfonyl)-amide anion, NMP and sulfolane. It was found that the investigated ionic liquid shows much higher selectivity at infinite dilution than the general used organic solvents such as NMP, sulfolane and other ionic liquids. Additionally the selectivities for selected compounds which form azeotropic mixtures were calculated.

Energy futures

International Nuclear Information System (INIS)

Treat, J.E.

1990-01-01

This book provides fifteen of the futures industry's leading authorities with broader background in both theory and practice of energy futures trading in this updated text. The authors review the history of the futures market and the fundamentals of trading, hedging, and technical analysis; then they update you with the newest trends in energy futures trading - natural gas futures, options, regulations, and new information services. The appendices outline examples of possible contracts and their construction

Portfolio Diversification with Commodity Futures: Properties of Levered Futures

NARCIS (Netherlands)

Woodard, J.D.; Egelkraut, T.M.; Garcia, P.; Pennings, J.M.E.

2005-01-01

Portfolio Diversification with Commodity Futures: Properties of Levered Futures This study extends previous work on the impact of commodity futures on portfolio performance by explicitly incorporating levered futures into the portfolio optimization problem. Using data on nine individual commodity

Foundations of a discrete physics

International Nuclear Information System (INIS)

McGoveran, D.; Noyes, P.

1988-01-01

Starting from the principles of finiteness, discreteness, finite computability and absolute nonuniqueness, we develop the ordering operator calculus, a strictly constructive mathematical system having the empirical properties required by quantum mechanical and special relativistic phenomena. We show how to construct discrete distance functions, and both rectangular and spherical coordinate systems(with a discrete version of ''π''). The richest discrete space constructible without a preferred axis and preserving translational and rotational invariance is shown to be a discrete 3-space with the usual symmetries. We introduce a local ordering parameter with local (proper) time-like properties and universal ordering parameters with global (cosmological) time-like properties. Constructed ''attribute velocities'' connect ensembles with attributes that are invariant as the appropriate time-like parameter increases. For each such attribute, we show how to construct attribute velocities which must satisfy the '' relativistic Doppler shift'' and the ''relativistic velocity composition law,'' as well as the Lorentz transformations. By construction, these velocities have finite maximum and minimum values. In the space of all attributes, the minimum of these maximum velocities will predominate in all multiple attribute computations, and hence can be identified as a fundamental limiting velocity, General commutation relations are constructed which under the physical interpretation are shown to reduce to the usual quantum mechanical commutation relations. 50 refs., 18 figs

Effective gravitational wave stress-energy tensor in alternative theories of gravity

International Nuclear Information System (INIS)

Stein, Leo C.; Yunes, Nicolas

2011-01-01

The inspiral of binary systems in vacuum is controlled by the stress-energy of gravitational radiation and any other propagating degrees of freedom. For gravitational waves, the dominant contribution is characterized by an effective stress-energy tensor at future null infinity. We employ perturbation theory and the short-wavelength approximation to compute this stress-energy tensor in a wide class of alternative theories. We find that this tensor is generally a modification of that first computed by Isaacson, where the corrections can dominate over the general relativistic term. In a wide class of theories, however, these corrections identically vanish at asymptotically flat, future, null infinity, reducing the stress-energy tensor to Isaacson's. We exemplify this phenomenon by first considering dynamical Chern-Simons modified gravity, which corrects the action via a scalar field and the contraction of the Riemann tensor and its dual. We then consider a wide class of theories with dynamical scalar fields coupled to higher-order curvature invariants and show that the gravitational wave stress-energy tensor still reduces to Isaacson's. The calculations presented in this paper are crucial to perform systematic tests of such modified gravity theories through the orbital decay of binary pulsars or through gravitational wave observations.

Null Geodesic Congruences, Asymptotically-Flat Spacetimes and Their Physical Interpretation

Directory of Open Access Journals (Sweden)

Timothy M. Adamo

2009-09-01

Full Text Available A priori, there is nothing very special about shear-free or asymptotically shear-free null geodesic congruences. Surprisingly, however, they turn out to possess a large number of fascinating geometric properties and to be closely related, in the context of general relativity, to a variety of physically significant effects. It is the purpose of this paper to try to fully develop these issues. This work starts with a detailed exposition of the theory of shear-free and asymptotically shear-free null geodesic congruences, i.e., congruences with shear that vanishes at future conformal null infinity. A major portion of the exposition lies in the analysis of the space of regular shear-free and asymptotically shear-free null geodesic congruences. This analysis leads to the space of complex analytic curves in complex Minkowski space. They in turn play a dominant role in the applications. The applications center around the problem of extracting interior physical properties of an asymptotically-flat spacetime directly from the asymptotic gravitational (and Maxwell field itself, in analogy with the determination of total charge by an integral over the Maxwell field at infinity or the identification of the interior mass (and its loss by (Bondi’s integrals of the Weyl tensor, also at infinity. More specifically, we will see that the asymptotically shear-free congruences lead us to an asymptotic definition of the center-of-mass and its equations of motion. This includes a kinematic meaning, in terms of the center-of-mass motion, for the Bondi three-momentum. In addition, we obtain insights into intrinsic spin and, in general, angular momentum, including an angular-momentum–conservation law with well-defined flux terms. When a Maxwell field is present, the asymptotically shear-free congruences allow us to determine/define at infinity a center-of-charge world line and intrinsic magnetic dipole moment.

Null Geodesic Congruences, Asymptotically-Flat Spacetimes and Their Physical Interpretation

Directory of Open Access Journals (Sweden)

Timothy M. Adamo

2012-01-01

Full Text Available A priori, there is nothing very special about shear-free or asymptotically shear-free null geodesic congruences. Surprisingly, however, they turn out to possess a large number of fascinating geometric properties and to be closely related, in the context of general relativity, to a variety of physically significant effects. It is the purpose of this paper to try to fully develop these issues. This work starts with a detailed exposition of the theory of shear-free and asymptotically shear-free null geodesic congruences, i.e., congruences with shear that vanishes at future conformal null infinity. A major portion of the exposition lies in the analysis of the space of regular shear-free and asymptotically shear-free null geodesic congruences. This analysis leads to the space of complex analytic curves in an auxiliary four-complex dimensional space, H-space. They in turn play a dominant role in the applications. The applications center around the problem of extracting interior physical properties of an asymptotically-flat spacetime directly from the asymptotic gravitational (and Maxwell field itself, in analogy with the determination of total charge by an integral over the Maxwell field at infinity or the identification of the interior mass (and its loss by (Bondi's integrals of the Weyl tensor, also at infinity. More specifically, we will see that the asymptotically shear-free congruences lead us to an asymptotic definition of the center-of-mass and its equations of motion. This includes a kinematic meaning, in terms of the center-of-mass motion, for the Bondi three-momentum. In addition, we obtain insights into intrinsic spin and, in general, angular momentum, including an angular-momentum--conservation law with well-defined flux terms. When a Maxwell field is present, the asymptotically shear-free congruences allow us to determine/define at infinity a center-of-charge world line and intrinsic magnetic dipole moment.

Null Geodesic Congruences, Asymptotically-Flat Spacetimes and Their Physical Interpretation.

Science.gov (United States)

Adamo, Timothy M; Newman, Ezra T; Kozameh, Carlos

2012-01-01

A priori, there is nothing very special about shear-free or asymptotically shear-free null geodesic congruences. Surprisingly, however, they turn out to possess a large number of fascinating geometric properties and to be closely related, in the context of general relativity, to a variety of physically significant effects. It is the purpose of this paper to try to fully develop these issues. This work starts with a detailed exposition of the theory of shear-free and asymptotically shear-free null geodesic congruences, i.e., congruences with shear that vanishes at future conformal null infinity. A major portion of the exposition lies in the analysis of the space of regular shear-free and asymptotically shear-free null geodesic congruences. This analysis leads to the space of complex analytic curves in an auxiliary four-complex dimensional space, [Formula: see text]-space. They in turn play a dominant role in the applications. The applications center around the problem of extracting interior physical properties of an asymptotically-flat spacetime directly from the asymptotic gravitational (and Maxwell) field itself, in analogy with the determination of total charge by an integral over the Maxwell field at infinity or the identification of the interior mass (and its loss) by (Bondi's) integrals of the Weyl tensor, also at infinity. More specifically, we will see that the asymptotically shear-free congruences lead us to an asymptotic definition of the center-of-mass and its equations of motion. This includes a kinematic meaning, in terms of the center-of-mass motion, for the Bondi three-momentum. In addition, we obtain insights into intrinsic spin and, in general, angular momentum, including an angular-momentum-conservation law with well-defined flux terms. When a Maxwell field is present, the asymptotically shear-free congruences allow us to determine/define at infinity a center-of-charge world line and intrinsic magnetic dipole moment.

Method of performing shutdown reactivity measurements in spent nuclear fuel storage pools

International Nuclear Information System (INIS)

Levine, S.H.; Schultz, M.A.; Chang, D.

1981-01-01

The objective of this paper is to develop a device to measure the k/infinity/ of a spent fuel assembly used in light water reactors. A subcritical assembly having a cross configuration is designed to allow measurement of the k/sub //infinity/ of a spent fuel assembly by comparing the change in its multiplication with that of a fuel assembly of known k/infinity/. Calculations have been performed using nucleonic codes to develop polynomial equations that relate the k/infinity/ of the spent fuel assembly to measured data. The measurements involve taking count rates with the spent fuel assembly in the center position of the subcritical assembly, and the measured data are the count rate ratio of the spent fuel assembly over the count rate taken with a fuel assembly of known k/infinity/. The polynomial equations are easy to program on a microcomputer, which, together with the subcritical assembly, form the k/infinity/ meter. 9 refs

Holography in asymptotically flat spacetimes and the BMS group

International Nuclear Information System (INIS)

Arcioni, Giovanni; Dappiaggi, Claudio

2004-01-01

In a previous paper (Arcioni G and Dappiaggi C 2003 Preprint hep-th/0306142) we have started to explore the holographic principle in the case of asymptotically flat spacetimes and analysed, in particular, different aspects of the Bondi-Metzner-Sachs (BMS) group, namely the asymptotic symmetry group of any asymptotically flat spacetime. We continue this investigation in this paper. Having in mind an S-matrix approach with future and past null infinity playing the role of holographic screens on which the BMS group acts, we connect the IR sectors of the gravitational field with the representation theory of the BMS group. We analyse the (complicated) mapping between bulk and boundary symmetries pointing out differences with respect to the anti-de Sitter (AdS)/CFT set up. Finally, we construct a BMS phase space and a free Hamiltonian for fields transforming with respect to BMS representations. The last step is supposed to be an explorative investigation of the boundary data living on the degenerate null manifold at infinity

Asymptotic cross sections for the excitation of atomic hydrogen by proton and alpha-particle impact

International Nuclear Information System (INIS)

Saha, H.P.; Saha, B.C.

1978-01-01

The total and the differential cross sections for the reactions H + + H(1s) → H + + H(infinity s, infinity p), He ++ + H(1s) → He ++ + H (infinity s, infinity p), have been calculated in the energy range 1 keV to 2 MeV using the first Born approximation. The transition amplitudes for the asymptotic region have been reduced to a simple closed form. Irrespective of the projectile energies it is observed that the asymptotic cross sections obey the inverse n-cube law. (Auth.)

Equation of states for the infinite cluster and backbone in anisotropic square lattice

International Nuclear Information System (INIS)

Silva, L.R. da; Almeida, N.S.; Tsallis, C.

1985-01-01

A real space renormalization group procedure recently developed for calculating equations of states for geometrical problems is used, to treat bond percolation in the anisotropic square lattice. By choosing a convenient self-dual cluster, for all values of the occupancy probabilities P sub(x) and P sub(y) (along the x and y axes respectively), the order parameters P infinity (P sub(x),P sub(y)) and P sup(B) infinity (P sub(x),P sub(y)) respectively associated with the complete percolating infinite cluster and with its backbone are calculated. An interesting difference appears between these two quantities whenever one of the occupancy probabilities, say P sub(y), equals unity: lim sub(P sub(y) → l) P infinity (P sub(x),P sub(y) is discontinuous at P sub(x)=0 (where P sub(infinity) jumps from 0 to 1), whereas lim sub(P sub(y) → 1) P sup(B) sub(infinity) (P sub(x),P sub(y)) continuously increases from 0 to 1 when P sub(x) increases from 0 to 1. Through a convenient extrapolation procedure which includes the use of the best available values for the critical exponents β and β sup(B), values for P sub(infinity) and P sup(B) sub(infinity) which are believed to be numerically quite reliable are obtained. In particular, P sub(infinity) (p,p) approx. A (p-1/2) sup(β) (β=5/36 and A approx. 1.25) and P sup(B) sub(infinity) (p,p) approx. A sup(B) (p-1/2) sup(β) sup(B) (β sup(B) approx. 0.53 and A sup(B) approx. 1.92). (Author) [pt

Time travel in the homogeneous Som-Raychaudhuri Universe

International Nuclear Information System (INIS)

Paiva, F.M.; Reboucas, M.J.; Teixeira, A.F.F.

1987-01-01

Properties of the rotating Som-Raychaudhuri homogeneous space-time are investigated: time-like and null geodesics, causality features, horizons and invariant characterization. An integral representation of its five isometries is also discussed. (author) [pt

Singularities of lightcone pedals of spacelike curves in Lorentz-Minkowski 3-space

Directory of Open Access Journals (Sweden)

Chen Liang

2016-01-01

Full Text Available In this paper, geometric properties of spacelike curves on a timelike surface in Lorentz-Minkowski 3-space are investigated by applying the singularity theory of smooth functions from the contact viewpoint.

Fit between Future Thinking and Future Orientation on Creative Imagination

Science.gov (United States)

Chiu, Fa-Chung

2012-01-01

The purpose of the current study is to investigate the impact of future thinking, and the fit between future thinking and future orientation on creative thinking. In Study 1, 83 undergraduates were randomly assigned to three groups: 50-year future thinking, 5-year future thinking, and the present-day thinking. First, the priming tasks, in which…

MALBEC: a new CUDA-C ray-tracer in general relativity

Science.gov (United States)

Quiroga, G. D.

2018-06-01

A new CUDA-C code for tracing orbits around non-charged black holes is presented. This code, named MALBEC, take advantage of the graphic processing units and the CUDA platform for tracking null and timelike test particles in Schwarzschild and Kerr. Also, a new general set of equations that describe the closed circular orbits of any timelike test particle in the equatorial plane is derived. These equations are extremely important in order to compare the analytical behavior of the orbits with the numerical results and verify the correct implementation of the Runge-Kutta algorithm in MALBEC. Finally, other numerical tests are performed, demonstrating that MALBEC is able to reproduce some well-known results in these metrics in a faster and more efficient way than a conventional CPU implementation.

Probing the non-classicality of temporal correlations

Directory of Open Access Journals (Sweden)

Martin Ringbauer

2017-11-01

Full Text Available Correlations between spacelike separated measurements on entangled quantum systems are stronger than any classical correlations and are at the heart of numerous quantum technologies. In practice, however, spacelike separation is often not guaranteed and we typically face situations where measurements have an underlying time order. Here we aim to provide a fair comparison of classical and quantum models of temporal correlations on a single particle, as well as timelike-separated correlations on multiple particles. We use a causal modeling approach to show, in theory and experiment, that quantum correlations outperform their classical counterpart when allowed equal, but limited communication resources. This provides a clearer picture of the role of quantum correlations in timelike separated scenarios, which play an important role in foundational and practical aspects of quantum information processing.

Quantum mechanics of time travel through post-selected teleportation

International Nuclear Information System (INIS)

Lloyd, Seth; Garcia-Patron, Raul; Maccone, Lorenzo; Giovannetti, Vittorio; Shikano, Yutaka

2011-01-01

This paper discusses the quantum mechanics of closed-timelike curves (CTCs) and of other potential methods for time travel. We analyze a specific proposal for such quantum time travel, the quantum description of CTCs based on post-selected teleportation (P-CTCs). We compare the theory of P-CTCs to previously proposed quantum theories of time travel: the theory is inequivalent to Deutsch's theory of CTCs, but it is consistent with path-integral approaches (which are the best suited for analyzing quantum-field theory in curved space-time). We derive the dynamical equations that a chronology-respecting system interacting with a CTC will experience. We discuss the possibility of time travel in the absence of general-relativistic closed-timelike curves, and investigate the implications of P-CTCs for enhancing the power of computation.

On the quark-antiquark potential at short distances

International Nuclear Information System (INIS)

Altevogt, P.

1994-12-01

We investigate the static quark-antiquark potential up to distances of 8 lattice units for pure SU(2) gauge theory on lattices with anisotropic couplings. The action is the Wilson action with a coupling fro time-like plaquettes which differs from those for space-like ones. Numerical simulations are performed in a large range of β. The potential is obtained by fitting 'cooled' Wilson loops with up to 4 exponential terms. An interpolation of the potentials by a sum of a perturbative term, a linear term and by lattice artifacts shows poor scaling in comparison with the isotropic case. If the coupling in the time-like region is reduced, the linear term is much smaller than in the isotropic case, and vice versa. Consequences for the bag picture for hadrons are discussed. (orig.)

Calculation of {psi}, {phi} and of their derivatives; calcul de {psi}, {phi} et de leurs derivees

Energy Technology Data Exchange (ETDEWEB)

Dandeu, Y; Gautier, L; Guillermin, J; Olivie, G; Roche, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1965-07-01

The functions: {psi}(x,{beta}) = 1/{beta}{radical}{pi} {integral}{sub -{infinity}}{sup +{infinity}} [e{sup -(y-x/{beta}}{sup ){sup }}2/1+y{sup 2}] dx and {phi}(x,{beta}) = 1/{beta}{radical}{pi} {integral}-{infinity}+{infinity} [y e{sup -(y-x/{beta}}{sup ){sup }}2/1+y{sup 2}] dy as well as their primary and secondary derivatives with respect to x and {beta} have been calculated for the whole of the (x,{beta}) plane using a certain number of different methods: series development, asymptotic development, Hermites polynomials and approximating formulae. These methods have made it possible to conserve a constant relative accuracy, except in the neighbourhood of the regions where the derivatives disappear. (authors) [French] Les fonctions: {psi}(x,{beta}) = 1/{beta}{radical}{pi} {integral}{sub -{infinity}}{sup +{infinity}} [e{sup -(y-x/{beta}}{sup ){sup }}2/1+y{sup 2}] dx and {phi}(x,{beta}) = 1/{beta}{radical}{pi} {integral}-{infinity}+{infinity} [y e{sup -(y-x/{beta}}{sup ){sup }}2/1+y{sup 2}] dy ainsi que leurs derivees premieres et secondes par rapport a x et a {beta} ont pu etre calculees dans tout le plan (x,{beta}) en faisant appel a un certain nombre de methodes differentes: developpement en serie, developpement asymptotique, polynomes d'Hermites, et formules approchees. Ces methodes ont permis de conserver une precision relative constante, sauf au voisinage des zones d'annulation des derivees. (auteurs)

A dimension decomposition approach based on iterative observer design for an elliptic Cauchy problem

KAUST Repository

Majeed, Muhammad Usman; Laleg-Kirati, Taous-Meriem

2015-01-01

A state observer inspired iterative algorithm is presented to solve boundary estimation problem for Laplace equation using one of the space variables as a time-like variable. Three dimensional domain with two congruent parallel surfaces

Procrastination, consideration of future consequences, and episodic future thinking.

Science.gov (United States)

Rebetez, Marie My Lien; Barsics, Catherine; Rochat, Lucien; D'Argembeau, Arnaud; Van der Linden, Martial

2016-05-01

Despite the intrinsic temporal nature of procrastination, little research has examined the link between this form of self-regulatory failure and the consideration of future consequences, and no study has addressed the link between procrastination and episodic future thinking. The aim of the present study was to explore these relationships. Participants were asked to project themselves into possible future events and to rate the amount of sensory-perceptual details and autonoetic consciousness associated with their representations. They were also asked to complete questionnaires that assessed procrastination, the consideration of future consequences, and negative affect. Results showed that both the consideration of future consequences and episodic future thinking were associated with procrastination, and in particular with procrastination-related decision making abilities and procrastination-related motivational dispositions, respectively. Copyright © 2016 Elsevier Inc. All rights reserved.

Feynman rules of quantum chromodynamics inside a hadron

International Nuclear Information System (INIS)

Lee, T.D.

1979-01-01

We start from quantum chromodynamics in a finite volume of linear size L and examine its color-dielectric constant kappa/sub L/, especially the limit kappa/sub infinity/ as L → infinity. By choosing as our standard kappa/sub L/ = 1 when L = some hadron size R, we conclude that kappa/sub infinity/ must be -2 α where α is the fine-structure constant of QCD inside the hadron. A permanent quark confinement corresponds to the limit kappa/sub infinity/ = 0. The hadrons are viewed as small domain structures (with color-dielectric constant = 1) immersed in a perfect, or nearly perfect, color-dia-electric medium, which is the vacuum. The Feynman rules of QCD inside the hadron are derived; they are found to depend on the color-dielectric constant kappa/sub infinity/ of the vacuum that lies outside. We show that, when kappa/sub infinity/ → 0, the mass of any color-nonsinglet state becomes infinity, but for color-singlet states their masses and scattering amplitudes remain finite. These new Feynman rules also depend on the hadron size R. Only at high energy and large four-momentum transfer can such R dependence be neglected and, for color-singlet states, these new rules be reduced to the usual ones

Risk factors for acute generalized exanthematous pustulosis (AGEP)-results of a multinational case-control study (EuroSCAR).

Science.gov (United States)

Sidoroff, A; Dunant, A; Viboud, C; Halevy, S; Bavinck, J N Bouwes; Naldi, L; Mockenhaupt, M; Fagot, J-P; Roujeau, J-C

2007-11-01

Acute generalized exanthematous pustulosis (AGEP) is a disease characterized by the rapid occurrence of many sterile, nonfollicular pustules usually arising on an oedematous erythema often accompanied by leucocytosis and fever. It is usually attributed to drugs. To evaluate the risk for different drugs of causing AGEP. A multinational case-control study (EuroSCAR) conducted to evaluate the risk for different drugs of causing severe cutaneous adverse reactions; the study included 97 validated community cases of AGEP and 1009 controls. Results Strongly associated drugs, i.e. drugs with a lower bound of the 95% confidence interval (CI) of the odds ratio (OR) > 5 were pristinamycin (CI 26-infinity), ampicillin/amoxicillin (CI 10-infinity), quinolones (CI 8.5-infinity), (hydroxy)chloroquine (CI 8-infinity), anti-infective sulphonamides (CI 7.1-infinity), terbinafine (CI 7.1-infinity) and diltiazem (CI 5.0-infinity). No significant risk was found for infections and a personal or family history of psoriasis (CI 0.7-2.2). Medications associated with AGEP differ from those associated with Stevens-Johnson syndrome or toxic epidermal necrolysis. Different timing patterns from drug intake to reaction onset were observed for different drugs. Infections, although possible triggers, played no prominent role in causing AGEP and there was no evidence that AGEP is a variant of pustular psoriasis.

Inhaled indacaterol for the treatment of COPD patients with destroyed lung by tuberculosis and moderate-to-severe airflow limitation: results from the randomized INFINITY study.

Science.gov (United States)

Kim, Cheong-Ju; Yoon, Hyoung-Kyu; Park, Myung-Jae; Yoo, Kwang-Ha; Jung, Ki-Suck; Park, Jeong-Woong; Lim, Seong Yong; Shim, Jae Jeong; Lee, Yong Chul; Kim, Young-Sam; Oh, Yeon-Mok; Kim, Song; Yoo, Chul-Gyu

2017-01-01

Pulmonary tuberculosis (TB) is a risk factor for chronic obstructive pulmonary disease (COPD); however, few clinical studies have investigated treatment effectiveness in COPD patients with destroyed lung by TB. The Indacaterol effectiveness in COPD patients with Tuberculosis history (INFINITY) study assessed the efficacy and safety of once-daily inhaled indacaterol 150 µg for the treatment of Korean COPD patients with destroyed lung by TB and moderate-to-severe airflow limitation. This was a multicenter, double-blind, parallel-group study, in which eligible patients were randomized (1:1) to receive either once-daily indacaterol 150 µg or placebo for 8 weeks. The primary efficacy endpoint was change from baseline in trough forced expiratory volume in 1 s at Week 8; the secondary endpoints included changes in transition dyspnea index score and St George's Respiratory Questionnaire for COPD score at Week 8. Safety was evaluated over 8 weeks. Of the 136 patients randomized, 119 (87.5%) completed the study treatment. At Week 8, indacaterol significantly improved trough forced expiratory volume in 1 s versus placebo (treatment difference [TD] 140 mL, P <0.001). Statistically significant improvement in transition dyspnea index score (TD =0.78, P <0.05) and numerical improvement in St George's Respiratory Questionnaire for COPD score (TD =-2.36, P =0.3563) were observed with indacaterol versus placebo at Week 8. Incidence of adverse events was comparable between the treatment groups. Indacaterol provided significantly superior bronchodilation, significant improvement in breathlessness and improved health status with comparable safety versus placebo in Korean COPD patients with destroyed lung by TB and moderate-to-severe airflow limitation.

49 CFR Appendix A-I to Part 541 - Lines With Antitheft Devices Which Are Exempted From the Parts-Marking Requirements of This...

Science.gov (United States)

2010-10-01

.... Outlander.1 Nissan Altima. Cube.1 Maxima. Murano. Pathfinder. Quest. Rogue. Sentra. Versa. Infiniti G.2 Infiniti M.3 Porsche 911. Boxster/Cayman. Panamera. Saab 9-3. 9-5.1 Subaru Forester. Impreza. Legacy.1 B9.... Tiguan.1 1 Granted an exemption from the parts marking requirements beginning with MY 2011. 2 Infiniti G...

The Future Multiple

DEFF Research Database (Denmark)

Spaniol, Matthew Jon; Rowland, Nicholas James

2015-01-01

/value – The original contribution is in demonstrating how plural futures and the singular future co-exist in practice. Thus, an eclipse of the future by futures can only ever be partial. For “futures” to be conceptually potent, “the future” must be at least provisionally believable and occasionally useful. Otherwise......, if “the future” were so preposterous an idea, then “futures” would cease to be a critical alternative to it. Futures needs the future; they are relationally bound together in a multiplicity. This paper considers what such a logical reality implies for a field that distances itself from the future and self......). Multiplicity, as a post-ANT sensibility, helps one make sense of the empirical materials. This paper examines the possibility that rather than being alternatives to one another, plural futures and the singular future might co-exist in practice, and, thus, constitute a multiplicity. Design...

Temperature determination from a real plasma from line self-reversal

International Nuclear Information System (INIS)

Salakhov, M.K.; Fishman, I.S.

1981-01-01

The coefficient Z = M/sub infinity/Y/sub infinity/ is determined on the basis of the actual structure of a plasma (the M/sub infinity/ and Y/sub infinity/ coefficients in Bartels's theory). The absorption and emission spectra are utilized as recorded in a transverse section of the plasma, which are used in determining the actual course of the atomic concentration and the half-width of the thin-layer line. An iterative scheme is set up for determining the temperature. A mathematical experiment has been performed and the temperature distribution has been determined in the plasma of a low-voltage pulsed discharge

A weak zero-one law for sequences of random distance graphs

Energy Technology Data Exchange (ETDEWEB)

Zhukovskii, Maksim E [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation)

2012-07-31

We study zero-one laws for properties of random distance graphs. Properties written in a first-order language are considered. For p(N) such that pN{sup {alpha}}{yields}{infinity} as N{yields}{infinity}, and (1-p)N{sup {alpha}} {yields} {infinity} as N {yields} {infinity} for any {alpha}>0, we succeed in refuting the law. In this connection, we consider a weak zero-one j-law. For this law, we obtain results for random distance graphs which are similar to the assertions concerning the classical zero-one law for random graphs. Bibliography: 18 titles.

Lessons from the British Defeat Combating Colonial Hybrid Warfare in the 1781 Southern Theater of Operations

Science.gov (United States)

2014-05-22

Society for Army Historical Research 16, no. 61 (1937): 3-23; Henry Clinton, The Headquarters Papers of the British Army in North America During the War...Rejoinder to ‘Future Threats and Strategic Thinking,” Infinity Journal 2, no. 2 (Spring 2012): 24-29. 19Department of the Army, ADRP 3-0, Unified Land...represented his security zone. The colony provided food for Greene’s army, a staging base for manufactured material and forces from New England, and a

Modular structure of the local algebras associated with the free massless scalar field theory

International Nuclear Information System (INIS)

Hislop, P.D.; Longo, R.

1982-01-01

The modular structure of the von Neuman algebra of local observables associated with a double cone in the vacuum representation of the free massless scalar field theory of any number of dimensions is described. The modular automorphism group is induced by the unitary implementation of a family of generalized fractional linear transformations on Minkowski space and is a subgroup of the conformal group. The modular conjugation operator is the anti-unitary impementation of a product of time reversal and relativistic ray inversion. The group generated by the modular conjugation operators for the local algebras associated with the family of double cone regions is the group of proper conformal transformations. A theorem is presented asserting the unitary equivalence of local algebras associated with lightcones, double cones and wedge regions. For the double cone algebras, this provides an explicitly realization of spacelike duality and establishes the known type III 1 factor property. It is shown that the timelike duality property of the lightcone algebras does not hold for the double cone algebras. A different definition of the von Neumann algebras associated with a region is introduced which agrees with the standard one for a lightcone or a double cone region but which allows the timelike duality property for the double cone algebras. In the case of one spatial dimension, the standard local algebras associated with the double cone regions satisfy both specelike and timelike duality. (orig.)

Charge changing processes in the formation of fast H0 atoms

International Nuclear Information System (INIS)

Anderson, C.J.

1979-01-01

Measurements are reported of the charge changing cross sections sigma- 0 , sigma-/sub +/, sigma/sub g+/ sigma/sub g-/ for H - ions incident on Ne, Ar, Kr, Xe, Li, Na, K, Rb and Cs targets in the energy range 25 to 200 keV. The maximum neutral fractions, F 0 /sup max/, for H - ions incident on H 2 , D 2 , CO 2 , H 2 O, C 4 H 10 , C 5 H 12 , CF 4 , CHF 3 , CClF 3 , CBrF 3 , acetone, 2-propanol and natural gas have been measured in the energy range 30 to 200 keV. The largest neutral fraction for 100 keV H - is 0.631 produced in a Li vapor target. The equilibrium fractions F/sub -//sup infinity/, F 0 /sup infinity/ and F/sub +//sup infinity/ for H - ions incident on H 2 , He, Ne, Ar, Kr, Xe, Li, Na, K, Rb and Cs have been measured in the energy range 30 to 200 keV. Also measured are the cross sections sigma/sub +0/ and sigma/sub +-/ and the equilibrium fractions F/sub -//sup infinity/, F 0 /sup infinity/ and F/sub +//sup infinity/ for H + incident on a Na target in the energy range 1-25 keV. The largest value of F/sub -//sup infinity/ is 0.101 for H + incident at 2 keV

Quantum mechanics, relativity and casuality

International Nuclear Information System (INIS)

Tati, T.

1976-01-01

In quantum mechanics, the state is prepared by a measurement on a spacelike surface sigma. What is that determine the surface sigma on which the measurement prepares the stae. It si considered either a mechanism proper to the measuring process (apparatus) or a universal property of space-time. In the former case, problems arise, concerning casuality or conservation of probability due to the fact that the velocity of reduction of a wave packet is considered to exceed the light velocity. The theory of finite degree of freedom proposed previously belongs to the latter case. In this theory, the surface sigma is restricted to the hyper-plane perpendicular to a universal time-like vector governing casual relations. An experimental to discriminate between the above-mentioned two cases and to test the existence of the universal timelike vector is proposed

Supersymmetric solutions of minimal gauged supergravity in five dimensions

International Nuclear Information System (INIS)

Gauntlett, Jerome P.; Gutowski, Jan B.

2003-01-01

All purely bosonic supersymmetric solutions of minimal gauged supergravity in five dimensions are classified. The solutions fall into two classes depending on whether the Killing vector constructed from the Killing spinor is timelike or null. When it is timelike, the solutions are determined by a four-dimensional Kaehler base manifold, up to an antiholomorphic function, are necessarily not static, and generically preserve 1/2 of the supersymmetry. When it is null we provide a precise prescription for constructing the solutions and we show that they generically preserve 1/4 of the supersymmetry. We show that five-dimensional anti-de Sitter space (AdS 5 ) is the unique maximally supersymmetric configuration. The formalism is used to construct some new solutions, including a nonsingular deformation of AdS 5 , which can be uplifted to obtain new solutions of type IIB supergravity

Quantum mechanics, relativity and causality

International Nuclear Information System (INIS)

Tati, Takao.

1975-07-01

In quantum mechanics, the state is prepared by a measurement on a space-like surface sigma. What is that determines the surface sigma on which the measurement prepares the state It is considered either a mechanism proper to the measuring process (apparatus) or a universal property of space-time. In the former case, problems arise, concerning causality or conservation of probability due to that the velocity of reduction of wave-packet is considered to exceed the light velocity. The theory of finite degree of freedom proposed previously belongs to the latter case. In this theory, the surface sigma is restricted to the hyper-plane perpendicular to a universal time-like vector governing causal relations. We propose an experiment to discriminate between the above-mentioned two cases and to test the existence of the universal time-like vector. (auth.)

On the next-to-next-to-leading order evolution of flavour-singlet fragmentation functions

International Nuclear Information System (INIS)

Almasy, A.A.; Moch, S.; Vogt, A.

2012-01-01

We present the third-order contributions to the quark-gluon and gluon-quark timelike splitting functions for the evolution of fragmentation functions in perturbative QCD. These quantities have been derived by studying physical evolution kernels for photon- and Higgs-exchange structure functions in deep-inelastic scattering and their counterparts in semi-inclusive annihilation, together with constraints from the momentum sum rule and the supersymmetric limit. For this purpose we have also calculated the second-order coefficient functions for one-hadron inclusive Higgs decay in the heavy-top limit. A numerically tolerable uncertainty remains for the quark-gluon splitting function, which does not affect the endpoint logarithms for small and large momentum fractions. We briefly discuss these limits and illustrate the numerical impact of the third-order corrections. Compact and accurate parametrizations are provided for all third-order timelike splitting functions.

Charmless decays of the B-meson in perturbative QCD

International Nuclear Information System (INIS)

Libo Guo; Dongsheng Du; Lianshou Liu

1999-01-01

Using the perturbative QCD method and Chau's six-quark-graph scheme, we report a theoretical calculation of exclusive nonleptonic decays of the B meson into two light pseudoscalar mesons in the context of the low-energy effective Hamiltonian. The contributions from both tree-level and one-loop diagrams are taken into account. Under the approximation of neglecting light quark and light meson masses, we find that (i) within perturbative QCD there is no singularity which exists in the computation of spacelike penguin diagrams when the BSW model is used; (ii) the contributions from spacelike-type (W-annihilation, W-exchange, spacelike penguin and penguin-annihilation) graphs are strongly suppressed relative to those from timelike-type (external W-emission, internal W-emission and timelike penguin) ones; (iii) our results are well below the experimental upper limits but lower than the BSW ones. (author)

On the next-to-next-to-leading order evolution of flavour-singlet fragmentation functions

Energy Technology Data Exchange (ETDEWEB)

Almasy, A.A.; Vogt, A. [Liverpool Univ. (United Kingdom). Dept. of Mathematical Sciences; Moch, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

2011-07-15

We present the third-order contributions to the quark-gluon and gluon-quark timelike splitting functions for the evolution of fragmentation functions in perturbative QCD. These quantities have been derived by studying physical evolution kernels for photon- and Higgs-exchange structure functions in deep-inelastic scattering and their counterparts in semi-inclusive annihilation, together with constraints from the momentum sum rule and the supersymmetric limit. For this purpose we have also calculated the second-order coefficient functions for one-hadron inclusive Higgs decay in the heavy-top limit. A numerically tolerable uncertainty remains for the quark-gluon splitting function, which does not affect the endpoint logarithms for small and large momentum fractions. We briefly discuss these limits and illustrate the numerical impact of the third-order corrections. Compact and accurate parametrizations are provided for all third-order timelike splitting functions. (orig.)

Multifactor valuation models of energy futures and options on futures

Science.gov (United States)

Bertus, Mark J.

The intent of this dissertation is to investigate continuous time pricing models for commodity derivative contracts that consider mean reversion. The motivation for pricing commodity futures and option on futures contracts leads to improved practical risk management techniques in markets where uncertainty is increasing. In the dissertation closed-form solutions to mean reverting one-factor, two-factor, three-factor Brownian motions are developed for futures contracts. These solutions are obtained through risk neutral pricing methods that yield tractable expressions for futures prices, which are linear in the state variables, hence making them attractive for estimation. These functions, however, are expressed in terms of latent variables (i.e. spot prices, convenience yield) which complicate the estimation of the futures pricing equation. To address this complication a discussion on Dynamic factor analysis is given. This procedure documents latent variables using a Kalman filter and illustrations show how this technique may be used for the analysis. In addition, to the futures contracts closed form solutions for two option models are obtained. Solutions to the one- and two-factor models are tailored solutions of the Black-Scholes pricing model. Furthermore, since these contracts are written on the futures contracts, they too are influenced by the same underlying parameters of the state variables used to price the futures contracts. To conclude, the analysis finishes with an investigation of commodity futures options that incorporate random discrete jumps.

About one Newell's result and the quantum mechanical check of the microcanonical distribution

International Nuclear Information System (INIS)

Zastavenko, L.G.

1981-01-01

G.F. Newell succeeded to prove for the eigenfunctions PSIsub(n)(x) of the k-dimensional Schroedinger equation (-Δsub(k)+q(xsub(1), xsub(2)..., xsub(k))-lambdasub(n))PSIsub(n)(x)=0, ∫/PSIsup(2)(x)/dsup(k)x=1, q(x)>=0, q(x)→+infinity at x→infinity the asymptotic relation (lambda→+infinity) Σsub(lambdasub(n) [ru

Eying the future: Eye movement in past and future thinking.

Science.gov (United States)

El Haj, Mohamad; Lenoble, Quentin

2017-06-07

We investigated eye movement during past and future thinking. Participants were invited to retrieve past events and to imagine future events while their scan path was recorded by an eye-tracker. Past thinking triggered more fixation (p thinking. Past and future thinking triggered a similar duration of fixations and saccades, as well as a similar amplitude of saccades. Interestingly, participants rated past thinking as more vivid than future thinking (p thinking seems to be accompanied by an increased number of fixations and saccades. Fixations and saccades in past thinking can be interpreted as an attempt by the visual system to find (through saccades) and activate (through fixations) stored memory representations. The same interpretation can be applied to future thinking as this ability requires activation of past experiences. However, future thinking triggers fewer fixations and saccades than past thinking: this may be due to its decreased demand on visual imagery, but could also be related to a potentially deleterious effect of eye movements on spatial imagery required for future thinking. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Poincaré compactification of the MIC-Kepler problem with positive energies

CERN Document Server

Iwai, T

2001-01-01

The Poincare compactification and the symplectic reduction methods are first reviewed and then used to study the behaviour at infinity of the MIC (McIntosh-Cisneros)-Kepler problem at positive energies. The hyperbolic orbits leave the unstable equilibrium point set at infinity and tend eventually to the stable equilibrium point set at infinity. Both of these equilibrium point sets are diffeomorphic with S/sup 2/, the unit sphere in R/sup 3/. The hyperbolic orbits determine a map of the unstable equilibrium point set to the stable equilibrium point set in such a manner that the initial point (or the limit point as t to - infinity ) of an orbit is mapped to its final point (or the limit point as t to infinity ). This map is found explicitly as a rotation matrix which depends on the energy and the angular momentum of the orbits. (9 refs).

Making the future palpable: Notes from a major incident Future Laboratory

DEFF Research Database (Denmark)

Büscher, Monika; Kristensen, Margit; Mogensen, Preben Holst

2008-01-01

In this paper we describe experiences from a Future Laboratory. Future laboratories allow users to experiment with prototypes of future technologies in as realistic as possible conditions. We have devised this method because, to realize the potential of advanced ubiquitous computing technologies...... it is essential to anticipate and design for future practices, but for prospective users it is often difficult to imagine and articulate future practices and provide design specifications. However, they readily invent new ways of working in engagement with new technologies and, by facilitating realistic use...... of prototype technologies in Future Laboratories, designers and users can define and study both opportunities and constraints for design. We present 11 scenes from a Major Incidents Future Laboratory held in September 2005. Many raise tough questions rather than provide quick answers. In addition, many also...

Half-supersymmetric solutions in five-dimensional supergravity

International Nuclear Information System (INIS)

Gutowski, Jan B.; Sabra, Wafic

2007-01-01

We present a systematic classification of half-supersymmetric solutions of gauged N = 2, D = 5 supergravity coupled to an arbitrary number of abelian vector multiplets for which at least one of the Killing spinors generate a time-like Killing vector

Future planning - utopia

International Nuclear Information System (INIS)

Boernke, F.

1978-01-01

Our life develops as the anticipation of future. Everything we wish, hope, plan and carry out and think is or should be related to future and will have its effects in future. The certainty may spread that it is a necessary obligation to learn to find out our actual being more clearly to be able to develop a thinking and acting that is directed to future that has also a total of responsability as its essence. We will later atone for the failed outlooks into future or for only moderate or uncompleted starts of planning. For this reason we should consider that future does not come for its own, not without our demands, not without our acting. Only if our reflection and aspiration, thinking and acting is done with moderate and circumspect sense in the right way it will be a good fundamental for the future. (orig.) [de

Asymptotic conditions and conserved quantities

International Nuclear Information System (INIS)

Koul, R.K.

1990-01-01

Two problems have been investigated in this dissertation. The first one deals with the relationship between stationary space-times which are flat at null infinity and stationary space-times which are asymptotic flat at space-like infinity. It is shown that the stationary space-times which are asymptotically flat, in the Penrose sense, at null infinity, are asymptotically flat at space-like infinity in the Geroch sense and metric at space like infinity is at least C 1 . In the converse it is shown that the stationary space-times which are asymptotically flat at space like infinity, in the Beig sense, are asymptotically flat at null infinity in the Penrose sense. The second problem addressed deals with the theories of arbitrary dimensions. The theories treated are the ones which have fiber bundle structure, outside some compact region. For these theories the criterion for the choice of the background metric is specified, and the boundary condition for the initial data set (q ab , P ab ) is given in terms of the background metric. Having these boundary conditions it is shown that the symplectic structure and the constraint functionals are well defined. The conserved quantities associated with internal Killing vector fields are specified. Lastly the energy relative to a fixed background and the total energy of the theory have been given. It is also shown that the total energy of the theory is independent of the choice of the background

The Man Who Knew Infinity

Indian Academy of Sciences (India)

his work. Ramanujan did mathematics for its own sake, for the thrill that he got in seeing and discovering ... in those times led to a frantic search for a job to earn an income. .... mathematics, a man whose career seems full of paradoxes and ...

4. Infinity and the Sublime

Directory of Open Access Journals (Sweden)

Karin Verelst

2013-12-01

Full Text Available In their recent work, L. Graham and J.-M. Kantor discuss a remarkable connection between diverging conceptions of the mathematical infinite in Russia and France at the beginning of the twentieth century and the religious convictions of their respective authors. They expand much more on the Russian side of the cultural equation they propose; I do believe, however, that the French (or rather ‘West European’ side is more complex than it seems, and that digging deeper into it is worthwhile. In this paper I shall therefore broaden the path laid out in Graham and Kantor’s work, by connecting two different strands of research concerning the origin of what I loosely call ‘formal’ ideas: firstly, the rich but complex relation between logic and rhetoric throughout European cultural history, and secondly, the impact of religious convictions on the formation of certain mathematical and scientific ideas during Renaissance and Early Modernity, especially but not exclusively in France.

Advances in Antithetic Time Series Analysis : Separating Fact from Artifact

Directory of Open Access Journals (Sweden)

Dennis Ridley

2016-01-01

Full Text Available The problem of biased time series mathematical model parameter estimates is well known to be insurmountable. When used to predict future values by extrapolation, even a de minimis bias will eventually grow into a large bias, with misleading results. This paper elucidates how combining antithetic time series' solves this baffling problem of bias in the fitted and forecast values by dynamic bias cancellation. Instead of growing to infinity, the average error can converge to a constant. (original abstract

Study and optimal correction of a systematic skew quadrupole field in the Tevatron

International Nuclear Information System (INIS)

Snopok, Pavel; Johnstone, Carol; Berz, Martin; Ovsyannikov, Dmitry A.; Ovsyannikov, Alexander D.

2006-01-01

Increasing demands for luminosity in existing and future colliders have made lattice design and error tolerance and correction critical to achieving performance goals. The current state of the Tevatron collider is an example, with a strong skew quadrupole error present in the operational lattice. This work studies the high-order performance of the Tevatron and the strong nonlinear behavior introduced when a significant skew quadrupole error is combined with conventional sextupole correction, a behavior still clearly evident after optimal tuning of available skew quadrupole circuits. An optimization study is performed using different skew quadrupole families, and, importantly, local and global correction of the linear skew terms in maps generated by the code COSY INFINITY [M. Berz, COSY INFINITY version 8.1 user's guide and reference manual, Department of Physics and Astronomy MSUHEP-20704, Michigan State University (2002). URL http://cosy.pa.msu.edu/cosymanu/index.html]. Two correction schemes with one family locally correcting each arc and eight independent correctors in the straight sections for global correction are proposed and shown to dramatically improve linearity and performance of the baseline Tevatron lattice

Radiative observables for linearized gravity on asymptotically flat spacetimes and their boundary induced states

International Nuclear Information System (INIS)

Benini, Marco; Dappiaggi, Claudio; Murro, Simone

2014-01-01

We discuss the quantization of linearized gravity on globally hyperbolic, asymptotically flat, vacuum spacetimes, and the construction of distinguished states which are both of Hadamard form and invariant under the action of all bulk isometries. The procedure, we follow, consists of looking for a realization of the observables of the theory as a sub-algebra of an auxiliary, non-dynamical algebra constructed on future null infinity ℑ + . The applicability of this scheme is tantamount to proving that a solution of the equations of motion for linearized gravity can be extended smoothly to ℑ + . This has been claimed to be possible provided that a suitable gauge fixing condition, first written by Geroch and Xanthopoulos [“Asymptotic simplicity is stable,” J. Math. Phys. 19, 714 (1978)], is imposed. We review its definition critically, showing that there exists a previously unnoticed obstruction in its implementation leading us to introducing the concept of radiative observables. These constitute an algebra for which a Hadamard state induced from null infinity and invariant under the action of all spacetime isometries exists and it is explicitly constructed

Calorimetric measurements on slightly soluble gases in water

International Nuclear Information System (INIS)

Olofsson, G.; Oshodj, A.A.; Qvarnstroem, E.; Wadsoe, I.

1984-01-01

Calorimetric measurements have been made of enthalpies of solution Δsub(sol)Hsub(m)sup(infinity) in water of helium, neon, argon, krypton, xenon, methane, ethane, propane, n-butane, and oxygen at 288.15, 298.15, and 308.15 K. Values of the heat-capacity changes Δsub(sol)Csub(p,m)sup(infinity) have been derived. The found values for both the enthalpy and heat-capacity changes for the rare gases and for oxygen fully confirm the values derived by Benson and Krause, Jr. (1976), and Benson, Krause, Jr., and Peterson (1979) from the results of their very careful gas-solubility measurements. The partial molar heat capacities Csub(p,2)sup(infinity) of the hydrocarbons studied were derived. The group-additivity schemes that have been used successfully for the estimation of values for Csub(p,2)sup(infinity) for various non-ionic organic compounds do not correctly predict values of Csub(p,2)sup(infinity) for the hydrocarbons in the present study. (author)

Sam Ting at the ISR intersection I-2 (experiment R209)

CERN Multimedia

CERN PhotoLab

1976-01-01

The Genova-Harvard-MIT-Pisa Collaboration, later CERN-Harvard-Frascati-MIT-Naples-Pisa Collaboration, set up an experiment to search for the electromagnetic properties of protons in the time-like region and search for the neutral boson Z0 (Muon pair production)

On the equivalence of electromagnetic and clock-transport synchronization in noninertial frames and gravitational fields

International Nuclear Information System (INIS)

Rumpf, H.

1984-01-01

Synchronization by slow clock transport is shown to be equivalent so that by electromagnetic signals for clocks moving along the trajectories of a timelike Killing vector field, provided the gravitational redshift is corrected for and the synchronization paths are the same. (Author)

Eigenvalue treatment of cosmological models

International Nuclear Information System (INIS)

Novello, M.; Soares, D.

1976-08-01

From the decomposition of Weyl tensor into its electric and magnetic parts, it is formulated the eigenvalue problem for cosmological models, and is used quasi-maxwellian form of Einstein's equation to propagate it along a time-like congruence. Three related theorems are presented

A new concept of wormholes and the Multiverse

Science.gov (United States)

Novikov, I. D.

2018-03-01

We review a new concept of wormholes. We classify the wormholes into three categories: static, space-like, and time-like, and discuss the properties of each category. The relation between wormholes and black holes is examined. The astrophysical properties of wormholes are investigated.

Vacuum counterexamples to the cosmic censorship hypothesis

International Nuclear Information System (INIS)

Miller, B.D.

1981-01-01

In cylindrically symmetric vacuum spacetimes it is possible to specify nonsingular initial conditions such that timelike singularities will (necessarily) evolve from these conditions. Examples are given; the spacetimes are somewhat analogous to one of the spherically symmetric counterexamples to the cosmic censorship hypothesis

Shanghai Futures Exchange Published Draft of Tin and Nickel Futures Contract

Institute of Scientific and Technical Information of China (English)

2015-01-01

Shanghai Futures Exchange published draft for soliciting opinions for tin and nickel futures contract on its official website on January 19,which implies the marketing time of the long awaited tin and nickel futures is drawing near.According to the draft for soliciting opinions,the transaction unit of tin futures contract is 1tonne/lot,minimum variation unit is 10 yuan/tonne,daily maximum price fluctuation shall

Future-Oriented LCA

DEFF Research Database (Denmark)

Olsen, Stig Irving; Borup, Mads; Andersen, Per Dannemand

2018-01-01

LCA is often applied for decision-making that concerns actions reaching near or far into the future. However, traditional life cycle assessment methodology must be adjusted for the prospective and change-oriented purposes, but no standardised way of doing this has emerged yet. In this chapter some...... challenges are described and some learnings are derived. Many of the future-oriented LCAs published so far perform relatively short-term prediction of simple comparisons. But for more long-term time horizons foresight methods can be of help. Scenarios established by qualified experts about future...... technological and economic developments are indispensable in future technology assessments. The uncertainties in future-oriented LCAs are to a large extent qualitative and it is important to emphasise that LCA of future technologies will provide a set of answers and not ‘the’ answer....

Rotating black string with nonlinear source

International Nuclear Information System (INIS)

Hendi, S. H.

2010-01-01

In this paper, we derive rotating black string solutions in the presence of two kinds of nonlinear electromagnetic fields, so-called Born-Infeld and power Maxwell invariant. Investigation of the solutions show that for the Born-Infeld black string the singularity is timelike and the asymptotic behavior of the solutions is anti-de Sitter, but for power Maxwell invariant solutions, depending on the values of nonlinearity parameter, the singularity may be timelike as well as spacelike and the solutions are not asymptotically anti-de Sitter for all values of the nonlinearity parameter. Next, we calculate the conserved quantities of the solutions by using the counterterm method, and find that these quantities do not depend on the nonlinearity parameter. We also compute the entropy, temperature, the angular velocity, the electric charge, and the electric potential of the solutions, in which the conserved and thermodynamics quantities satisfy the first law of thermodynamics.

Extra-Dimensional “Metamaterials”: A Model of Inflation Due to a Metric Signature Transition

Directory of Open Access Journals (Sweden)

Igor I. Smolyaninov

2017-09-01

Full Text Available Lattices of topological defects, such as Abrikosov lattices and domain wall lattices, often arise as metastable ground states in higher-dimensional field theoretical models. We demonstrate that such lattice states may be described as extra-dimensional “metamaterials” via higher-dimensional effective medium theory. A 4 + 1 dimensional extension of Maxwell electrodynamics with a compactified time-like dimension is considered as an example. It is demonstrated that from the point of view of macroscopic electrodynamics an Abrikosov lattice state in such a 4 + 1 dimensional spacetime may be described as a uniaxial hyperbolic medium. Extraordinary photons perceive this medium as a 3 + 1 dimensional Minkowski spacetime in which one of the original spatial dimensions plays the role of a new time-like coordinate. Since the metric signature of this effective spacetime depends on the Abrikosov lattice periodicity, the described model may be useful in studying metric signature transitions.

Expanding perfect fluid generalizations of the C metric

International Nuclear Information System (INIS)

Wylleman, Lode; Beke, David

2010-01-01

Petrov type D gravitational fields, generated by a perfect fluid with spatially homogeneous energy density and with flow lines which form a nonshearing and nonrotating timelike congruence, are reexamined. It turns out that the anisotropic such spacetimes, which comprise the vacuum C metric as a limit case, can have nonzero expansion, contrary to the conclusion in the original investigation by Barnes [A. Barnes, Gen. Relativ. Gravit. 4, 105 (1973).]. Apart from the static members, this class consists of cosmological models with precisely one symmetry. The general line element is constructed and some important properties are discussed. It is also shown that purely electric Petrov type D vacuum spacetimes admit shear-free normal timelike congruences everywhere, even in the nonstatic regions. This result incited to deduce intrinsic, easily testable criteria regarding shear-free normality and staticity of Petrov type D spacetimes in general, which are added in an appendix.

On the many saddle points description of quantum black holes

Energy Technology Data Exchange (ETDEWEB)

Germani, Cristiano, E-mail: cristiano.germani@physik.uni-muenchen.de

2014-06-02

Considering two dimensional gravity coupled to a CFT, we show that a semiclassical black hole can be described in terms of two Liouville theories matched at the horizon. The black hole exterior corresponds to a space-like while the interior to a time-like Liouville theory. This matching automatically implies that a semiclassical black hole has an infinite entropy. The path integral description of the time-like Liouville theory (the Black Hole interior) is studied and it is found that the correlation functions of the coupled CFT-gravity system are dominated by two (complex) saddle points, even in the semiclassical limit. We argue that this system can be interpreted as two interacting Bose–Einstein condensates constructed out of two degenerate quantum states. In AdS/CFT context, the same system is mapped into two interacting strings intersecting inside a three-dimensional BTZ black hole.

Quantum effective potential in S1xR3

International Nuclear Information System (INIS)

Denardo, G.; Spallucci, E.; Doebner, H.D.

1981-07-01

The functional integral formulation of quantum field theory is applied to the study of the vacuum state in spacetimes with S 1 xR 3 topology. Such a global spacetime structure can be physically realized both in flat and in curved spacetime. In the first case one deals with finite temperature quantum field theories (if S 1 is time-like) or with field theories in a spacetime with a compact space dimension (if S 1 is spacelike). When curvature is present, a S 1 time-like dimension is induced by the Wick rotation whenever the metric is endowed with an event horizon, and this leads to the thermal nature of the vacuum in these cases. We shall take into account here only conformally flat spacetimes. Finally we discuss in some details the topological restoration of a spontaneously broken symmetry and the strictly related problem of the mass dynamical generation. (author)

A novel biological 'twin-father' temporal paradox of General Relativity in a Gödel universe - Where reproductive biology meets theoretical physics.

Science.gov (United States)

Ashrafian, Hutan

2018-03-01

Several temporal paradoxes exist in physics. These include General Relativity's grandfather and ontological paradoxes and Special Relativity's Langevin-Einstein twin-paradox. General relativity paradoxes can exist due to a Gödel universe that follows Gödel's closed timelike curves solution to Einstein's field equations. A novel biological temporal paradox of General Relativity is proposed based on reproductive biology's phenomenon of heteropaternal fecundation. Herein, dizygotic twins from two different fathers are the result of concomitant fertilization during one menstrual cycle. In this case an Oedipus-like individual exposed to a Gödel closed timelike curve would sire a child during his maternal fertilization cycle. As a consequence of heteropaternal superfecundation, he would father his own dizygotic twin and would therefore generate a new class of autofraternal superfecundation, and by doing so creating a 'twin-father' temporal paradox. Copyright © 2017 Elsevier Ltd. All rights reserved.

Asymptotic structure of isolated systems

International Nuclear Information System (INIS)

Schmidt, B.G.

1979-01-01

The main methods to formulate asymptotic flatness conditions are introduced and motivation and basic ideas are emphasized. Any asymptotic flatness condition proposed up to now describes space-times which behave somehow like Minkowski space, and a very explicit exposition of the structure at infinity of Minkowski space is given. This structure is used to describe the asymptotic behaviour of fields on Minkowski space in a frame-dependent way. The definition of null infinity for curved space-time according to Penrose is given and attempts to define spacelike infinity are outlined. The conformal bundle approach to the formulation of asymptotic behaviour is described and its relation to null and spacelike infinity is given, as far as known. (Auth.)

Constraints on the gravitational constant from observations of white dwarfs

International Nuclear Information System (INIS)

Blinnikov, S.I.

1978-01-01

Recently some authors have questioned whether Newton's law of gravitation is actually true on scales less than 1 km. The available constraints on the gravitational constant show that its laboratory value G 0 may differ from the value at infinity Gsub(infinity) by approximately 40%. Long (1976) reported experimental evidence for departures from Newton's law. In this note it is shown that the difference between G 0 and Gsub(infinity) modifies the mass-radius relation of degenerate stars. The observations of white dwarfs are consistent with the theory of stellar evolution only if G 0 differs from Gsub(infinity) by not more than approximately 10%. This estimate may be improved by a higher accuracy of observations. (Auth.)

Renewable Electricity Futures Study. Volume 1. Exploration of High-Penetration Renewable Electricity Futures

Energy Technology Data Exchange (ETDEWEB)

Hand, M. M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Baldwin, S. [U.S. Dept. of Energy, Washington, DC (United States); DeMeo, E. [Renewable Energy Consulting, Chicago, IL (United States); Reilly, J. M. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Mai, T. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Arent, D. [Joint Inst. for Strategic Energy Analysis, Boulder, CO (United States); Porro, G. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Meshek, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sandor, D. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2012-06-15

The Renewable Electricity Futures (RE Futures) Study investigated the challenges and impacts of achieving very high renewable electricity generation levels in the contiguous United States by 2050. The analysis focused on the sufficiency of the geographically diverse U.S. renewable resources to meet electricity demand over future decades, the hourly operational characteristics of the U.S. grid with high levels of variable wind and solar generation, and the potential implications of deploying high levels of renewables in the future. RE Futures focused on technical aspects of high penetration of renewable electricity; it did not focus on how to achieve such a future through policy or other measures. Given the inherent uncertainties involved with analyzing alternative long-term energy futures as well as the multiple pathways that might be taken to achieve higher levels of renewable electricity supply, RE Futures explored a range of scenarios to investigate and compare the impacts of renewable electricity penetration levels (30%–90%), future technology performance improvements, potential constraints to renewable electricity development, and future electricity demand growth assumptions. RE Futures was led by the National Renewable Energy Laboratory (NREL) and the Massachusetts Institute of Technology (MIT). Learn more at the RE Futures website. http://www.nrel.gov/analysis/re_futures/

Money market futures

OpenAIRE

Anatoli Kuprianov

1992-01-01

Virtually all financial innovation in the U.S. money market during the past 20 years has centered on interest rate derivatives, including futures and swaps. Furthermore, money market futures--especially futures contracts on Eurodollar time deposits--have been at the vanguard of the recent explosion of trading activity in interest rate derivatives. While futures markets traditionally have been viewed as markets for the transfer of price risk, recent research shows that they may serve other imp...

Future accelerators (?)

Energy Technology Data Exchange (ETDEWEB)

John Womersley

2003-08-21

I describe the future accelerator facilities that are currently foreseen for electroweak scale physics, neutrino physics, and nuclear structure. I will explore the physics justification for these machines, and suggest how the case for future accelerators can be made.

The Jacobi metric for timelike geodesics in static spacetimes

Science.gov (United States)

Gibbons, G. W.

2016-01-01

It is shown that the free motion of massive particles moving in static spacetimes is given by the geodesics of an energy-dependent Riemannian metric on the spatial sections analogous to Jacobi's metric in classical dynamics. In the massless limit Jacobi's metric coincides with the energy independent Fermat or optical metric. For stationary metrics, it is known that the motion of massless particles is given by the geodesics of an energy independent Finslerian metric of Randers type. The motion of massive particles is governed by neither a Riemannian nor a Finslerian metric. The properies of the Jacobi metric for massive particles moving outside the horizon of a Schwarschild black hole are described. By constrast with the massless case, the Gaussian curvature of the equatorial sections is not always negative.

Geodesic in Godel type universes

International Nuclear Information System (INIS)

Galvao, M.O.

1985-01-01

We find out the timelike and null geodesics of a certain family of Goedel-like universes, carrying out, at first, a qualitative analysis through the method of the effective potential and, subsequently, proceeding to the exact integration of the equations of motion. (author) [pt

Ghost quintessence in fractal gravity

Indian Academy of Sciences (India)

In this study, using the time-like fractal theory of gravity, we mainly focus on the ghost ... Here a(t) is the cosmic scale factor and it measures the expansion of the Universe. ..... effectively appear as self-conserved dark energy, with a non-trivial ...

Infinitely many inequivalent field theories from one Lagrangian

CERN Document Server

100__; Mavromatos, Nick E.; Sarkar, Sarben

2014-01-01

Logarithmic time-like Liouville quantum field theory has a generalized PT invariance, where T is the time-reversal operator and P stands for an S-duality reflection of the Liouville field $\\phi$. In Euclidean space the Lagrangian of such a theory, $L=\\frac{1}{2}(\

Renewable Electricity Futures Study. Volume 1: Exploration of High-Penetration Renewable Electricity Futures

Energy Technology Data Exchange (ETDEWEB)

Mai, T.; Wiser, R.; Sandor, D.; Brinkman, G.; Heath, G.; Denholm, P.; Hostick, D.J.; Darghouth, N.; Schlosser, A.; Strzepek, K.

2012-06-01

The Renewable Electricity Futures (RE Futures) Study investigated the challenges and impacts of achieving very high renewable electricity generation levels in the contiguous United States by 2050. The analysis focused on the sufficiency of the geographically diverse U.S. renewable resources to meet electricity demand over future decades, the hourly operational characteristics of the U.S. grid with high levels of variable wind and solar generation, and the potential implications of deploying high levels of renewables in the future. RE Futures focused on technical aspects of high penetration of renewable electricity; it did not focus on how to achieve such a future through policy or other measures. Given the inherent uncertainties involved with analyzing alternative long-term energy futures as well as the multiple pathways that might be taken to achieve higher levels of renewable electricity supply, RE Futures explored a range of scenarios to investigate and compare the impacts of renewable electricity penetration levels (30%-90%), future technology performance improvements, potential constraints to renewable electricity development, and future electricity demand growth assumptions. RE Futures was led by the National Renewable Energy Laboratory (NREL) and the Massachusetts Institute of Technology (MIT).

Towards Narrative Futuring in Psychology: Becoming Resilient by Imagining the Future

NARCIS (Netherlands)

Sools, Anna Maria; Mooren, J.H.M.

2012-01-01

In this article we develop a narrative psychological approach to futuring (imagining the future). We explore how this approach addresses the question of how people can become resilient in order to anticipate (social) crisis and change. Firstly, we bring to the fore how futuring takes shape in

Making the Future Palpable

DEFF Research Database (Denmark)

Büscher, Monika; Kristensen, Margit; Mogensen, Preben Holst

2007-01-01

In this paper we describe experiences from a Future Laboratory. Future laboratories allow users to experiment with prototypes of future technologies in as realistic as possible conditions. We have devised this method because, to realize the potential of advanced ubiquitous computing technologies...... it is essential to anticipate and design for future practices, but for prospective users it is often difficult to imagine and articulate future practices and provide design specifications. They readily invent new ways of working in engagement with new technologies, through and, by facilitating as realistic...... as possible use of prototype future technologies in Future Laboratories designers and users can define and study both opportunities and constraints for design. We present 11 scenes from a Major Incidents Future Laboratory held in September 2005. In relation to each scene we point out key results. Many raise...

78 FR 69880 - Notice of Determinations Regarding Eligibility To Apply for Worker Adjustment Assistance

Science.gov (United States)

2013-11-21

... of America, Internal Call Fresno, CA. Center. 83,067 Infiniti Plastic Technologies Paducah, KY. Inc., Infiniti Media Inc. 83,092 Green Mountain Power Corporation, Colchester, VT. Northern New England Energy...

Automation of complex assays: pharmacogenetics of warfarin dosing.

Science.gov (United States)

Wu, Whei-Kuo; Hujsak, Paul G; Kureshy, Fareed

2007-10-01

AutoGenomics, Inc. (Carlsbad, CA, USA) have developed a multiplex microarray assay for genotyping both VKORC1 and CYP2C9 using the INFINITI(™) Analyzer. Multiple alleles in each DNA sample are analyzed by polymerase chain reaction amplification, followed by detection primer extension using the INFINITI Analyzer. The INFINITI Analyzer performs single-nucleotide polymorphism (SNP) analysis using universal oligonucleotides immobilized on the biochip. To genotype broader ethnic groups, genomic DNA from whole blood was tested for nine SNPs for VKORC1 and six for CYP2C9 genotypes. Information related to all 15 SNPs is needed to determine dosing of population of diverse ethnic origin. The INFINITI system provides genotyping information for same day dosing of warfarin.

Activity coefficients at infinite dilution measurements for organic solutes and water in the ionic liquid 4-methyl-N-butyl-pyridinium bis(trifluoromethylsulfonyl)-imide

Energy Technology Data Exchange (ETDEWEB)

Domanska, Urszula [Physical Chemistry Department, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)], E-mail: ula@ch.pw.edu.pl; Marciniak, Andrzej [Physical Chemistry Department, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)

2009-12-15

The activity coefficients at infinite dilution, {gamma}{sub 13}{sup {infinity}} for 36 solutes: alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, ethers, acetone, and water in the ionic liquid 4-methyl-N-butyl-pyridinium bis(trifluoromethylsulfonyl)-imide [bmPY][NTf{sub 2}] were determined by gas-liquid chromatography at temperatures from 298.15 K to 368.15 K. The partial molar excess enthalpies at infinite dilution values {delta}H{sub 1}{sup E,{infinity}} were calculated from the experimental {gamma}{sub 13}{sup {infinity}} values obtained over the temperature range. The selectivity for different separation problems were calculated from the {gamma}{sub 13}{sup {infinity}} and compared to the literature values for other ionic liquids, N-methyl-2-pyrrolidinone (NMP) and sulfolane.

Oscillation of two-dimensional linear second-order differential systems

International Nuclear Information System (INIS)

Kwong, M.K.; Kaper, H.G.

1985-01-01

This article is concerned with the oscillatory behavior at infinity of the solution y: [a, ∞) → R 2 of a system of two second-order differential equations, y''(t) + Q(t) y(t) = 0, t epsilon[a, ∞); Q is a continuous matrix-valued function on [a, ∞) whose values are real symmetric matrices of order 2. It is shown that the solution is oscillatory at infinity if the largest eigenvalue of the matrix integral/sub a//sup t/ Q(s) ds tends to infinity as t → ∞. This proves a conjecture of D. Hinton and R.T. Lewis for the two-dimensional case. Furthermore, it is shown that considerably weaker forms of the condition still suffice for oscillatory behavior at infinity. 7 references

Quantum field theory in the infinite temperature limit

International Nuclear Information System (INIS)

Jourjine, A.N.

1984-01-01

The T = infinity limit for renormalizable 4-dimensional Euclidean QFT is considered. A general arguement is presented in three examples: phi 3 , QED, QCD. Using an expansion of the Green's functions generating functional, it is shown at T = infinity quantum dynamics generally becomes 3 dimensional. All superficially divergent diagrams survive at T = infinity and ensure renormalization of effective dynamics. The correction to naive dimensional reduction is studied; appearance of ''electric'' masses in QED and QCD is shown to be the result of such a correction. A curious symmetry of the generating functional in QED and QCD, its implications and breaking by the thermal corrections of heavy modes are discussed. Presence of the symmetry implies survival of some fermion modes at T = infinity

Anticipating Their Future: Adolescent Values for the Future Predict Adult Behaviors

Science.gov (United States)

Finlay, Andrea K.; Wray-Lake, Laura; Warren, Michael; Maggs, Jennifer

2015-01-01

Adolescent future values--beliefs about what will matter to them in the future--may shape their adult behavior. Utilizing a national longitudinal British sample, this study examined whether adolescent future values in six domains (i.e., family responsibility, full-time job, personal responsibility, autonomy, civic responsibility, and hedonistic…

Greening the Future

Science.gov (United States)

Williamson, Norma Velia

2011-01-01

Because educators vicariously touch the future through their students, the author believes that they sometimes have the uncanny ability to see the future. One common future forecast is the phenomenal growth of green jobs in the emerging green economy, leading to the creation of the "Reach of the Sun" Solar Energy Academy at La Mirada…

Future perspectives

International Nuclear Information System (INIS)

Anon.

1987-01-01

International involvement in particle physics is what the International Committee for Future Accelerators (ICFA) is all about. At the latest Future Perspectives meeting at Brookhaven from 5-10 October (after a keynote speech by doyen Viktor Weisskopf, who regretted the emergence of 'a nationalistic trend'), ICFA reviewed progress and examined its commitments in the light of the evolving world particle physics scene. Particular aims were to review worldwide accelerator achievements and plans, to survey the work of the four panels, and to discuss ICFA's special role in future cooperation in accelerator construction and use, and in research and development work for both accelerators and for detectors

Ultrasonic spectroscopy study into the nature of a high-temperature phase transformation in V203

International Nuclear Information System (INIS)

Andrianov, G.O.; Drichko, I.L.; Lakhtman, B.D.

1978-01-01

The velocity of longitudinal sound wave propagation in V 2 O 3 vanadium sesquioxide was studied in the temperature range of 250-550 K in a wide range of ultrasound frequencies from 70 to 1500 MHz. The investigation was carried out in order to obtain the dynamic characteristics of the transition and to define the nature of high-temperature anomalies in V 2 O 3 . The sound velocity dispersion was observed. The frequency dependence of the sound velocity can be adequately described by the Mandelstam-Leontovich formula. Values and temperature dependences of tau, Vsub(infinity) and (Vsub(infinity)-Vsub(0)/Vsub(infinity) were calculated where tau is the relaxation time; Vsub(0), Vsub(infinity) are the values of velocitiea when ω→0 and ω→infinity respectively. The acoustic anomalies in the temperature range under investigation are shown to be well described qualitatively by the overlapping zone model. A deep maximum in the sound velocity at T=520 K can be explained by fluctuations in the neighbourhood of the magnetic phase transformation

Not my future? Core values and the neural representation of future events.

Science.gov (United States)

Brosch, Tobias; Stussi, Yoann; Desrichard, Olivier; Sander, David

2018-06-01

Individuals with pronounced self-transcendence values have been shown to put greater weight on the long-term consequences of their actions when making decisions. Using functional magnetic resonance imaging, we investigated the neural mechanisms underlying the evaluation of events occurring several decades in the future as well as the role of core values in these processes. Thirty-six participants viewed a series of events, consisting of potential consequences of climate change, which could occur in the near future (around 2030), and thus would be experienced by the participants themselves, or in the far future (around 2080). We observed increased activation in anterior VMPFC (BA11), a region involved in encoding the personal significance of future events, when participants were envisioning far future events, demonstrating for the first time that the role of the VMPFC in future projection extends to the time scale of decades. Importantly, this activation increase was observed only in participants with pronounced self-transcendence values measured by self-report questionnaire, as shown by a statistically significant interaction of temporal distance and value structure. These findings suggest that future projection mechanisms are modulated by self-transcendence values to allow for a more extensive simulation of far future events. Consistent with this, these participants reported similar concern ratings for near and far future events, whereas participants with pronounced self-enhancement values were more concerned about near future events. Our findings provide a neural substrate for the tendency of individuals with pronounced self-transcendence values to consider the long-term consequences of their actions.

Future Textiles

DEFF Research Database (Denmark)

Hansen, Anne-Louise Degn; Jensen, Hanne Troels Fusvad; Hansen, Martin

2011-01-01

Magasinet Future Textiles samler resultaterne fra projektet Future Textiles, der markedsfører området intelligente tekstiler. I magasinet kan man læse om trends, drivkræfter, udfordringer samt få ideer til nye produkter inden for intelligente tekstiler. Områder som bæredygtighed og kundetilpasning...

Scalar fields and cosmic censorship hypothesis in general relativity

International Nuclear Information System (INIS)

Parnovs'kij, S.L.; Gajdamaka, O.Z.

2004-01-01

We discuss an influence of the presence of some nonstandard scalar fields in the vicinity of naked time-like singularity on the type and properties of this singularity. The main goal is to study the validity of the Penrose's Cosmic Censorship hypothesis in the General Relativity

Environmental Scanning, Futures Research, Strategic Foresight and Organizational Future Orientation

DEFF Research Database (Denmark)

Rohrbeck, René; Bade, Manuel

to adjacent research disciplines. Through such integration and linkage research should produce better recommendations for managers on how to build an organizational future orientation, drive organizational adaptation, and make their firms robust towards external discontinuous change.......In this paper we explore the current understanding on how firms explore future changes and trends as well as plan their managerial responses. We review literature in four research streams: (1) environmental scanning, (2) futures research, (3) peripheral vision, and (4) corporate/strategic foresight....... Through the analysis of more than 250 articles we (a) trace the evolution over time, (b) highlight the linkages between the different research streams, and (c) give recommendations for future research. Overall we call for more cross-fertilization of the different research streams and a stronger linkage...

Comparison of vacuum rise time, vacuum limit accuracy, and occlusion break surge of 3 new phacoemulsification systems.

Science.gov (United States)

Han, Young Keun; Miller, Kevin M

2009-08-01

To compare vacuum rise time, vacuum limit accuracy, and occlusion break surge of 3 new phacoemulsification machines. Jules Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA. The vacuum rise time under normal and enhanced aspiration modes, vacuum limit accuracy, and occlusion break surge of the Infiniti Vision System, Stellaris Vision Enhancement System, and WhiteStar Signature Phacoemulsification System were tested. Vacuum rise time and limit accuracy were measured at limit settings of 400 mm Hg and 600 mm Hg. Surge area was recorded at vacuum limit settings of 200 mm Hg, 300 mm Hg, 400 mm Hg, and 500 mm Hg. The Infiniti had the fastest vacuum rise times under normal and enhanced aspiration modes. At 4 seconds, the vacuum limit accuracy was greatest with the Infiniti at the 400 mm Hg limit and the Signature at the 600 mm Hg limit. The Stellaris did not reach either vacuum target. The Infiniti performed better than the other 2 machines during testing of occlusion break surge at all vacuum limit settings above 200 mm Hg. Under controlled laboratory test conditions, the Infiniti had the fastest vacuum rise time, greatest vacuum limit accuracy at 400 mm Hg, and least occlusion break surge. These results can be explained by the lower compliance of the Infiniti system.

Hawking into Unruh mapping for embeddings of hyperbolic type

International Nuclear Information System (INIS)

Paston, S A

2015-01-01

We study the conditions of the existence of Hawking into Unruh mapping for hyperbolic (Fronsdal-type) metric embeddings into the Minkowski space, for which timelines are hyperbolas. Many examples are known for global embeddings into the Minkowskian spacetime (GEMS), with such mapping for physically interesting metrics with some symmetry. However, examples of embeddings, both smooth and hyperbolic, for which there is no mapping, were also given. In the present work we prove that Hawking into Unruh mapping takes place for a hyperbolic embedding of an arbitrary metric with a time-like Killing vector and a Killing horizon if the embedding of such type exists and smoothly covers the horizon. At the same time, we do not assume any symmetry (spherical, for example), except the time translational invariance, which corresponds to the existence of a time-like Killing vector. We show that the known examples of the absence of mapping do not satisfy the formulated conditions of its existence. (paper)

Stability of Einstein static state universe in the spatially flat branemodels

Energy Technology Data Exchange (ETDEWEB)

Zhang, Kaituo [Department of Physics, Anhui Normal University, Wuhu, Anhui 241000 (China); Wu, Puxun [Center for Nonlinear Science and Department of Physics, Ningbo University, Ningbo, Zhejiang 315211 (China); Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, Hunan 410081 (China); Center for High Energy Physics, Peking University, Beijing 100080 (China); Yu, Hongwei, E-mail: hwyu@hunnu.edu.cn [Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, Hunan 410081 (China); Center for Nonlinear Science and Department of Physics, Ningbo University, Ningbo, Zhejiang 315211 (China); Luo, Ling-Wei [Institute of Physics, Chiao Tung University, Hsinchu 300, Taiwan (China)

2016-07-10

With the assumption that a perfect fluid with a constant equation of state is the only energy component on the brane, we study the stability of Einstein static state solution under homogeneous and inhomogeneous scalar perturbations in both spatially flat Randall–Sundrum (RS) and Shtanov–Sahni (SS) braneworlds. We find that if the perfect fluid has a phantom-like property and the “Weyl fluid” originating from the projection of the bulk Weyl tensor onto the brane behaves like a radiation with positive energy density, the Einstein static state solution is stable in the SS braneworld, but unstable in the RS one. Furthermore, we demonstrate that the static state solution is also stable in the bulk with a timelike extra dimension. Thus, in the model where the extra dimension is timelike, our universe can stay at the Einstein static state past-eternally, which means that the big bang singularity might be resolved successfully by an emergent scenario.

On the structure of space-time caustics

International Nuclear Information System (INIS)

Rosquist, K.

1983-01-01

Caustics formed by timelike and null geodesics in a space-time M are investigated. Care is taken to distinguish the conjugate points in the tangent space (T-conjugate points) from conjugate points in the manifold (M-conjugate points). It is shown that most nonspacelike conjugate points are regular, i.e. with all neighbouring conjugate points having the same degree of degeneracy. The regular timelike T-conjugate locus is shown to be a smooth 3-dimensional submanifold of the tangent space. Analogously, the regular null T-conjugate locus is shown to be a smooth 2-dimensional submanifold of the light cone in the tangent space. The smoothness properties of the null caustic are used to show that if an observer sees focusing in all directions, then there will necessarily be a cusp in the caustic. If, in addition, all the null conjugate points have maximal degree of degeneracy (as in the closed Friedmann-Robertson-Walker universes), then the space-time is closed. (orig.)

Partially ordered sets, transfinite topology and the dimension of Cantorian-fractal spacetime

Energy Technology Data Exchange (ETDEWEB)

Marek-Crnjac, L. [Institute of Mathematics and Physics, University of Maribor (Slovenia)], E-mail: leila.marek@guest.arnes.si

2009-11-15

We introduce partially ordered sets and relate them to random Cantor sets of E-infinity theory. Subsequently we derive the dimensionality of Cantorian-fractal spacetime using posets and E-infinity transfinite Cantor sets.

Thermodynamic Calculation of the Distribution Coefficient Between the Liquid and Solid Phases of an Element in Dilute Solution in a Metal: Application to the Purification of Beryllium; Calcul Thermodynamique du Coefficient de Distribution Entre Phases Liquide et Solide d'un Element en Presence d'Autres Constituants en Solution Diluee dans un Metal: Application a la Purification du Beryllium

Energy Technology Data Exchange (ETDEWEB)

Desre, P. [Ecole Nationale Superieure d' Electrochimie et d' Electrometallurgie (France); Schaub, B. [Centre d' Etudes Nucleaires de Grenoble (France); Bonnier, I. E. [Ecole Nationale Superieure d' Electrochimie et d' Electrometallurgie, Grenoble (France)

1966-01-15

The authors calculate the distribution coefficient {Gamma}{sub i} between the liquid and solid phases of an element i in the presence of other elements j in a solvent M ({Gamma}{sub i} = x'{sub i}/x{sub i}, where x'{sub i} and x{sub i} are the atomic fractions of i in the solid and liquid phases respectively) from the thermodynamic properties of binary systems of the type (i, M), (j, M) and (i, j). They show that the interaction of all the elements present may, under certain conditions, strongly affect the value of the coefficient {Gamma}{sub i}. This effect is pronounced if the following condition is fulfilled: {gamma}{sup {infinity}}{sub i(M)}, {gamma}{sup {infinity}}{sub j(M)} > {gamma}{sup {infinity}}{sub ij} where {gamma}{sup {infinity}}{sub i(M)}, {gamma}{sup {infinity}}{sub j(M)} and {gamma}{sup {infinity}}{sub ij} are limiting activity coefficients of the constituents i and j in the (i, M) (j, M) and (i, j) liquid state systems. It is a simple matter to deduce from this condition an application to the purification of metals by the zone-melting method; the condition enables one to choose an element j which is added deliberately to a metal in order to facilitate the elimination-of an element i (subsequent elimination of the element j being also, of course, a simple matter). For example, the authors were able to confirm that the addition of aluminium to beryllium enables one to improve the elimination of iron during the purification of the beryllium by the zone-melting technique, the aluminium acting as a carrier. (author) [French] Les auteurs calculent le coefficient de distribution Greek-Capital-Letter-Gamma {sub i} entre phases liquide et solide d'un element i en presence d'autres elements j dans un solvant M ( Greek-Capital-Letter-Gamma {sub i} = x'{sub i}/x{sub i}, x'{sub i} et x{sub i} representant respectivement les fractions atomiques de i dans les phases solide et liquide), a partir des proprietes thermodynamiques des systemes binaires de type: (i, M

Spatial growth of fundamental solutions for certain perturbations of the harmonic oscillator

DEFF Research Database (Denmark)

Jensen, Arne; Yajima, Kenji

We consider the fundamental solution for the Cauchy problem for perturbations of the harmonic oscillator by time dependent potentials, which grow at spatial infinity slower than quadratic, but faster than linear functions, and whose Hessian matrices have a fixed sign. We prove that the fundamental...... solution at resonant times grows indefinitely at spatial infinity with the algebraic growth rate, which increases indefinitely, when the growth rate of perturbations at infinity decrease from the near quadratic to the near linear ones....

Spatial growth of fundamental solutions for certain perturbations of the harmonic oscillator

DEFF Research Database (Denmark)

Jensen, Arne; Yajima, Kenji

2010-01-01

We consider the fundamental solution for the Cauchy problem for perturbations of the harmonic oscillator by time dependent potentials which grow at spatial infinity slower than quadratic but faster than linear functions and whose Hessian matrices have a fixed sign. We prove that the fundamental...... solution at resonant times grows indefinitely at spatial infinity with an algebraic growth rate, which increases indefinitely when the growth rate of perturbations at infinity decreases from the near quadratic to the near linear ones....

On Regularly Varying and History-Dependent Convergence Rates of Solutions of a Volterra Equation with Infinite Memory

OpenAIRE

John A. D. Appleby

2010-01-01

We consider the rate of convergence to equilibrium of Volterra integrodifferential equations with infinite memory. We show that if the kernel of Volterra operator is regularly varying at infinity, and the initial history is regularly varying at minus infinity, then the rate of convergence to the equilibrium is regularly varying at infinity, and the exact pointwise rate of convergence can be determined in terms of the rate of decay of the kernel and the rate of growth of the initial history. ...

Impact ionization coefficients for electrons and holes in In0.14Ga0.86As

International Nuclear Information System (INIS)

Pearsall, T.P.; Nahory, R.E.; Pollack, M.A.

1975-01-01

We report the measurement of impact ionization rates for electrons and holes in the direct band-gap semiconductor alloy In 0 . 14 Ga 0 . 86 As. Our results show clearly that the ionization rate for holes is greater than that for electrons. The measurments were made for electric fields between 2.6times10 5 and 3.4times10 5 V cm -1 . In this range, the ionization coefficients can be expressed as α=α/sub infinity/ exp(-A/E) for electrons and β=β/sub infinity/ exp(-B/E) for holes with α/sub infinity/=1.0times10 9 cm -1 , A=3.6times10 6 V cm -1 , and β/sub infinity/=1.3times10 8 cm -1 , B=2.7times10 6 V cm -1

Driven by the future : Future time perspective across life domains and cultures

NARCIS (Netherlands)

Andre, L.

2018-01-01

Contemplating about the future is inevitable for our life and goal strivings. Consequently, Future Time Perspective (FTP) – individuals’ attitudes towards the future as a motivator for attitudes and behaviors – has been researched across disciplines and life domains. However, little is known about

Ghost quintessence in fractal gravity

Indian Academy of Sciences (India)

In this study, using the time-like fractal theory of gravity, we mainly focus on the ghost dark energy model which was recently suggested to explain the present acceleration of the cosmic expansion. Next, we establish a connection between the quintessence scalar field and fractal ghost dark energy density.

FUTURE CLIMATE ANALYSIS

International Nuclear Information System (INIS)

R.M. Forester

2000-01-01

This Analysis/Model Report (AMR) documents an analysis that was performed to estimate climatic variables for the next 10,000 years by forecasting the timing and nature of climate change at Yucca Mountain (YM), Nevada (Figure l), the site of a potential repository for high-level radioactive waste. The future-climate estimates are based on an analysis of past-climate data from analog meteorological stations, and this AMR provides the rationale for the selection of these analog stations. The stations selected provide an upper and a lower climate bound for each future climate, and the data from those sites will provide input to the infiltration model (USGS 2000) and for the total system performance assessment for the Site Recommendation (TSPA-SR) at YM. Forecasting long-term future climates, especially for the next 10,000 years, is highly speculative and rarely attempted. A very limited literature exists concerning the subject, largely from the British radioactive waste disposal effort. The discussion presented here is one method, among many, of establishing upper and lower bounds for future climate estimates. The method used here involves selecting a particular past climate from many past climates, as an analog for future climate. Other studies might develop a different rationale or select other past climates resulting in a different future climate analog

FUTURE CLIMATE ANALYSIS

Energy Technology Data Exchange (ETDEWEB)

R.M. Forester

2000-03-14

This Analysis/Model Report (AMR) documents an analysis that was performed to estimate climatic variables for the next 10,000 years by forecasting the timing and nature of climate change at Yucca Mountain (YM), Nevada (Figure l), the site of a potential repository for high-level radioactive waste. The future-climate estimates are based on an analysis of past-climate data from analog meteorological stations, and this AMR provides the rationale for the selection of these analog stations. The stations selected provide an upper and a lower climate bound for each future climate, and the data from those sites will provide input to the infiltration model (USGS 2000) and for the total system performance assessment for the Site Recommendation (TSPA-SR) at YM. Forecasting long-term future climates, especially for the next 10,000 years, is highly speculative and rarely attempted. A very limited literature exists concerning the subject, largely from the British radioactive waste disposal effort. The discussion presented here is one method, among many, of establishing upper and lower bounds for future climate estimates. The method used here involves selecting a particular past climate from many past climates, as an analog for future climate. Other studies might develop a different rationale or select other past climates resulting in a different future climate analog.

White paper on future technologies

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-12-15

This book describes the role of technology and challenge of future like why we focus on future technologies and future, human being and technology, methodology on development for future technologies such as global monitoring system for investigation on environmental change, investigation of research front for paper and patent and COMPAS, and domestic and foreign organization for discover on future technologies. It also introduces KISTI selection future technologies 500 : healthy society, smart society, safety society, and future technologies 500.

Episodic memory and future thinking during early childhood: Linking the past and future.

Science.gov (United States)

Cuevas, Kimberly; Rajan, Vinaya; Morasch, Katherine C; Bell, Martha Ann

2015-07-01

Despite extensive examination of episodic memory and future thinking development, little is known about the concurrent emergence of these capacities during early childhood. In Experiment 1, 3-year-olds participated in an episodic memory hiding task ("what, when, where" [WWW] components) with an episodic future thinking component. In Experiment 2, a group of 4-year-olds (including children from Experiment 1) participated in the same task (different objects and locations), providing the first longitudinal investigation of episodic memory and future thinking. Although children exhibited age-related improvements in recall, recognition, and binding of the WWW episodic memory components, there were no age-related changes in episodic future thinking. At both ages, WWW episodic memory performance was higher than future thinking performance, and episodic future thinking and WWW memory components were unrelated. These findings suggest that the WWW components of episodic memory are potentially less fragile than the future components when assessed in a cognitively demanding task. © 2015 Wiley Periodicals, Inc.

Future Expectations of High School Students In Southeastern Turkey: Factors behind Future Expectations

Directory of Open Access Journals (Sweden)

Hüseyin Şimşek

2012-01-01

Full Text Available This study was conducted to identify various future expectations of high school students in southeastern Turkey and factors behind their expectations. The sample of the study, which had a descriptive and associational survey design consisted of 1106 students randomly selected from 54 different high schools located in nine cities in southeastern Turkey. Data were collected through the “Future Expectation Scale (FES” developed by the researcher. Results indicated that personal and professional future, educational future, economic future and social future expectations of high school students in southeastern Turkey were generally above the average level. According to the study, being a teacher and a doctor took the first place among several professions to be further preferred by high school students. It was also concluded that future expectations of high school students did not differ on gender, high school type, CGPA, level of mother education, father’s occupation, family income level, the number of siblings, receiving pre-school education, and language spoken at home. On the other hand, future expectations of high school students were found to differ on the city where students being taught, grade level, corporal punishment, and tendency toward being a dropout.

Medial Temporal Lobe Contributions to Episodic Future Thinking: Scene Construction or Future Projection?

Science.gov (United States)

Palombo, D J; Hayes, S M; Peterson, K M; Keane, M M; Verfaellie, M

2018-02-01

Previous research has shown that the medial temporal lobes (MTL) are more strongly engaged when individuals think about the future than about the present, leading to the suggestion that future projection drives MTL engagement. However, future thinking tasks often involve scene processing, leaving open the alternative possibility that scene-construction demands, rather than future projection, are responsible for the MTL differences observed in prior work. This study explores this alternative account. Using functional magnetic resonance imaging, we directly contrasted MTL activity in 1) high scene-construction and low scene-construction imagination conditions matched in future thinking demands and 2) future-oriented and present-oriented imagination conditions matched in scene-construction demands. Consistent with the alternative account, the MTL was more active for the high versus low scene-construction condition. By contrast, MTL differences were not observed when comparing the future versus present conditions. Moreover, the magnitude of MTL activation was associated with the extent to which participants imagined a scene but was not associated with the extent to which participants thought about the future. These findings help disambiguate which component processes of imagination specifically involve the MTL. Published by Oxford University Press 2016.

Future Savvy

DEFF Research Database (Denmark)

Gordon, Adam

There's no shortage of predictions available to organizations looking to anticipate and profit from future events or trends. Apparently helpful forecasts are ubiquitous in everyday communications such as newspapers and business magazines, and in specialized sources such as government and think......-tank forecasts, consultant reports, and stock-market guides. These resources are crucial, but they are also of very mixed quality. How can decision-makers know which predictions to take seriously, which to be wary of, and which to throw out entirely? Future Savvy provides analytical filters to judging predictive...... systematic "forecast filtering" to reveal strengths and weakness in the predictions they face. Future Savvy empowers both business and policy/government decision-makers to use forecasts wisely and so improve their judgment in anticipating opportunities, avoiding threats, and managing uncertainty....

Governance of the future

DEFF Research Database (Denmark)

Galløe, Lotte Rannveig

a different future for both parents and children. Thus, the approach to PMTO as a technology of the future indicates its expected prevalence in the future and its attempt to reach in to the future becoming of the child. The technology’s involvement of the relatives and its orientation towards shaping......In my presentation I will explore the concept, ‘technology of the future’, in public governance. Public governance within social services aims at changing the existing conditions for the marginalized citizens including children with special needs. I pose the question: what happens if public...... governance seek to chance the possible future conditions and targets the marginalized child’s relatives? Parent Management Training (PMTO) is studied as a technology of the future that expands and transforms governance. PMTO targets parents with aggressive and asocial children and aims to “create the parent...

Objective measurement of postocclusion surge during phacoemulsification in human eye-bank eyes.

Science.gov (United States)

Georgescu, Dan; Payne, Marielle; Olson, Randall J

2007-03-01

To objectively compare the postocclusion vacuum surge among different phacoemulsification machines and devices. Experimental study. Infiniti, Legacy, Millennium, and Sovereign were tested in an eye-bank eye. All the machines were tested with 20-gauge non-ABS tips, 430 mm Hg vacuum pressure, 24 ml/minute aspiration rate, peristaltic pump, and 75 cm bottle height. In addition, Infiniti and Legacy were also tested with 20-gauge bypass tips (ABS), 125 cm bottle height, and 40 ml/minute flow rate. We also tested 19-gauge tips with Infiniti and Sovereign and the venturi pump for Millennium. Significant differences were found between all the machines tested with Millennium peristaltic generating the least and Millennium Venturi the most surge. ABS tips significantly decreased the surge for Legacy but not for Infiniti. Cruise Control (CC) had a significant effect on Sovereign but not on Millennium. Increasing the bottle height decreased surge while increasing the flow increased surge for both Infiniti and Legacy. The 19-gauge tips increased surge for both Infiniti and Sovereign. Surge varied over a range of 40 microm to more than 2 mm. ABS and CC decrease surge, especially when the machine is not functioning near the limits of surge prevention. Certain parameters, such as a 19-gauge tip and high flow, dramatically increased surge, whereas elevating the bottle ameliorates it. Understanding the impact of all these features will help in minimizing the problem.

Comparison of performance of three commercial platforms for warfarin sensitivity genotyping.

Science.gov (United States)

Babic, Nikolina; Haverfield, Eden V; Burrus, Julie A; Lozada, Anthony; Das, Soma; Yeo, Kiang-Teck J

2009-08-01

We performed a 3-way comparison on the Osmetech eSensor, AutoGenomics INFINITI, and a real-time PCR method (Paragonx reagents/Stratagene RT-PCR platform) for their FDA-cleared warfarin panels, and additional polymorphisms (CYP2C9*5, *6, and 11 and extended VKORC1 panels) where available. One hundred de-identified DNA samples were used in this IRB-approved study. Accuracy was determined by comparison of genotyping results across three platforms. Any discrepancy was resolved by bi-directional sequencing. The CYP4F2 on Osmetech was validated by bi-directional sequencing. Accuracies for CYP2C9*2 and *3 were 100% for all 3 platforms. VKORC1 3673 genotyping accuracies were 100% on eSensor and 97% on Infiniti. CYP2C9*5, *6 and *11 showed 100% concordance between eSensor and Infiniti. VKORC1 6484 and 9041 variants compared between ParagonDx and Infiniti analyzer were 100% (6484) and 99% (9041) concordant. CYP4F2 was 100% concordant with sequencing results. The time required to generate the results from automated DNA extraction-to-result was approximately 8h on Infiniti, and 4h on eSensor and ParagonDx, respectively. Overall, we observed excellent CYP2C9*2 and *3 genotyping accuracy for all three platforms. For VKORC1 3673 genotyping, eSensor demonstrated a slightly higher accuracy than the Infiniti, and CYP4F2 on Osmetech was 100% accurate.

[Colon adenoma detection using Kubelka-Munk spectral function of DNA and protein bands].

Science.gov (United States)

Wei, Hua-Jiang; Guo, Zhou-Yi; Xie, Shu-Sen; He, Bo-Hua; Li, Li-Bo; Chen, Xue-Mei; Wu, Guo-Yong; Lu, Jian-Jun

2009-06-01

Differential diagnosis of human colon adenoma was studied using the Kubelka-Munk spectral function of the DNA and protein absorption bands at 260 and 280 nm in vitro. Diffuse reflectance spectra of tissue were measured using a spectrophotometer with an integrating sphere attachment. The results of measurement showed that for the spectral range from 590 to 1 064 nm pathological changes of colon epithelial tissues were induced so that there were significant differences in the averaged values of the Kubelka-Munk function f(r infinity) and logarithmic Kubelka-Munk function log [f(r infinity)] of the DNA absorption bands at 260 nm between normal and adenomatous colon epithelial tissues, and the differences were 218% (p function f(r infinity) and logarithmic Kubelka-Munk function log [f(r infinity)] of the protein absorption bands at 280 nm between normal and adenomatous colon epithelial tissues, and the differences were 208% (p function f(r infinity) and logarithmic Kubelka-Munk function log [f(r infinity)] of the beta-carotene absorption bands at 480 nm between normal and adenomatous colon epithelial tissues, and the differences were 41.7% (p < 0.05) and 32.9% (p < 0.05) respectively. Obviously, pathological changes of colon epithelial tissues were induced so that there were significant changes in the contents of the DNA, protein and beta-carotene of colon epithelial tissues. The conclusion can be applied to rapid, low-cost and noninvasive optical biopsy of colon adenoma, and provides a useful reference.

Rigorous study of the gap equation for an inhomogeneous superconducting state near T/sub c/

International Nuclear Information System (INIS)

Hu, C.R.

1975-01-01

An analytical study of the gap equation in the Bogoliubov formulation is presented. The normal-superconducting phase boundary is simulated by the expression Δ (R/sup =/) = Δ/sub infinity/ tanh / α Δ/sub infinity/z/v/sub f/) theta(z) where Δ/sub infinity/(t) is the equilibrium gap, theta (z) a unit step function and v/sub f/ the Fermi velocity. The Bogoliubov-de Gennes equations are solved in a nonperturbative WKBJ approximation. The gap equation is expanded near T/sub c/ in powers of Δ/sub infinity/ and the major term is of the same order as that given by the Ginzburg-Landau-Gor'kov approximation. Discrepancies in the two values are discussed in detail. It is concluded that the present technique reproduces the Ginzburg-Landau-Gor'kov results except within a BCS coherence length. 25 references

Forbidden coupling and inhibited decay: a study of disconnection

International Nuclear Information System (INIS)

Bolzan, J.F.; Palmer, W.F.; Pinsky, S.S.

1975-01-01

An attempt is made to correlate deviation from ideal mixing mass formula, high energy scattering behavior, and violation of the Okubo-Zweig-Iizuka rule. Pole or cut nature of the intermediary is discussed. Timelike and spacelike forbidden communications are compared. Off-shell effects are examined. Some problems for phenomenology are revealed

Measurements of sigma (e+e-→μ+-μ-+) in the energy range 1.2-3.0 GeV

International Nuclear Information System (INIS)

Alles-Borelli, V.; Bernardini, M.; Bollini, D.; Giusti, P.; Massam, T.; Monari, L.; Palmonari, F.; Valenti, G.; Zichichi, A.

1975-01-01

The analysis of 1466 events of the type e + e - →μ +- μ -+ , in the time-like range from 1.44 to 9.00 GeV 2 , shows that the absolute value of the cross-section and its energy dependence follow QED expectations within (+- 3.2%) and (+- 1.2%), respectively. (Auth.)

A rotating string

International Nuclear Information System (INIS)

Jensen, B.

1993-06-01

The author presents a global solution of Einstein's equations which represents a rotating cosmic string with a finite coreradius. The importance of pressure for the generation of closed timelike curves outside the coreregion of such strings is clearly displayed in this model due to the simplicity of the source. 10 refs

Cosmic censorship and the dilaton

International Nuclear Information System (INIS)

Horne, J.H.; Horowitz, G.T.

1993-01-01

We investigate extremal electrically charged black holes in Einstein-Maxwell-dilaton theory with a cosmological constant inspired by string theory. These solutions are not static, and a timelike singularity eventually appears which is not surrounded by an event horizon. This suggests that cosmic censorship may be violated in this theory

Light cones in relativity: Real, complex, and virtual, with applications

International Nuclear Information System (INIS)

Adamo, T. M.; Newman, E. T.

2011-01-01

We study geometric structures associated with shear-free null geodesic congruences in Minkowski space-time and asymptotically shear-free null geodesic congruences in asymptotically flat space-times. We show how in both the flat and asymptotically flat settings, complexified future null infinity I C + acts as a ''holographic screen,'' interpolating between two dual descriptions of the null geodesic congruence. One description constructs a complex null geodesic congruence in a complex space-time whose source is a complex worldline, a virtual source as viewed from the holographic screen. This complex null geodesic congruence intersects the real asymptotic boundary when its source lies on a particular open-string type structure in the complex space-time. The other description constructs a real, twisting, shear-free or asymptotically shear-free null geodesic congruence in the real space-time, whose source (at least in Minkowski space) is in general a closed-string structure: the caustic set of the congruence. Finally we show that virtually all of the interior space-time physical quantities that are identified at null infinity I + (center of mass, spin, angular momentum, linear momentum, and force) are given kinematic meaning and dynamical descriptions in terms of the complex worldline.

On the speed towards the mean for continuous time autoregressive moving average processes with applications to energy markets

International Nuclear Information System (INIS)

Benth, Fred Espen; Taib, Che Mohd Imran Che

2013-01-01

We extend the concept of half life of an Ornstein–Uhlenbeck process to Lévy-driven continuous-time autoregressive moving average processes with stochastic volatility. The half life becomes state dependent, and we analyze its properties in terms of the characteristics of the process. An empirical example based on daily temperatures observed in Petaling Jaya, Malaysia, is presented, where the proposed model is estimated and the distribution of the half life is simulated. The stationarity of the dynamics yield futures prices which asymptotically tend to constant at an exponential rate when time to maturity goes to infinity. The rate is characterized by the eigenvalues of the dynamics. An alternative description of this convergence can be given in terms of our concept of half life. - Highlights: • The concept of half life is extended to Levy-driven continuous time autoregressive moving average processes • The dynamics of Malaysian temperatures are modeled using a continuous time autoregressive model with stochastic volatility • Forward prices on temperature become constant when time to maturity tends to infinity • Convergence in time to maturity is at an exponential rate given by the eigenvalues of the model temperature model

Spherically symmetric near-critical accretion onto neutron stars

International Nuclear Information System (INIS)

Miller, G.S.

1990-01-01

Numerical and approximate analytic solutions for time-independent, spherically symmetric, radiation pressure-dominated accretion flows are presented. For flows with luminosities at infinity, L-infinity, sufficiently close to the Eddington limit L-crit, the flow velocity profile is qualitatively different from the modified free-fall profile v(r) = (1 - L-infinity/L-crit)exp 1/2 (2GM/r)exp 1/2. Advective contributions to the comoving radiation flux decelerate the flow within a criical radius, and, in this settling region, the velocity of the flow decreases linearly with decreasing radius. 14 refs

Approach to asymptopia in electron-positron annihilation into hadrons

International Nuclear Information System (INIS)

Choudhury, D.K.

1975-01-01

Assuming CEA/SPEAR energies to be nonasymptotic and from the positivity of the parton mass squared, it is derived that the asymptotic ratio Rsub(infinity) should lie within the interval [6.69+-1.00,7.77+-1.00]. Rsub(infinity) is the limit ratio of the cross sections of the reactions e + e - →hadrons and e + e - →μ + μ - respectively, as s tends to infinity. Present estimate is based on the application of leading-order finite-mass correction to the light-cone algebra/parton model in the non-asymptotic region

Future Contingents

DEFF Research Database (Denmark)

Øhrstrøm, Peter; Hasle., Per F. V.

2015-01-01

contingent statements. The problem of future contingents is interwoven with a number of issues in theology, philosophy, logic, semantics of natural language, computer science, and applied mathematics. The theological issue of how to reconcile the assumption of God's foreknowledge with the freedom and moral...... accountability of human beings has been a main impetus to the discussion and a major inspiration to the development of various logical models of time and future contingents. This theological issue is connected with the general philosophical question of determinism versus indeterminism. Within logic, the relation...... about the future. Finally, it should be mentioned that temporal logic has found a remarkable application in computer science and applied mathematics. In the late 1970s the first computer scientists realised the relevance of temporal logic for the purposes of computer science (see Hasle and Øhrstrøm 2004)....

Future Contingents

DEFF Research Database (Denmark)

Øhrstrøm, Peter; Hasle., Per F. V.

2011-01-01

contingent statements. The problem of future contingents is interwoven with a number of issues in theology, philosophy, logic, semantics of natural language, computer science, and applied mathematics. The theological issue of how to reconcile the assumption of God's foreknowledge with the freedom and moral...... accountability of human beings has been a main impetus to the discussion and a major inspiration to the development of various logical models of time and future contingents. This theological issue is connected with the general philosophical question of determinism versus indeterminism. Within logic, the relation...... about the future. Finally, it should be mentioned that temporal logic has found a remarkable application in computer science and applied mathematics. In the late 1970s the first computer scientists realised the relevance of temporal logic for the purposes of computer science (see Hasle and Øhrstrøm 2004)....

Causal structure and algebraic classification of non-dissipative linear optical media

International Nuclear Information System (INIS)

Schuller, Frederic P.; Witte, Christof; Wohlfarth, Mattias N.R.

2010-01-01

In crystal optics and quantum electrodynamics in gravitational vacua, the propagation of light is not described by a metric, but an area metric geometry. In this article, this prompts us to study conditions for linear electrodynamics on area metric manifolds to be well-posed. This includes an identification of the timelike future cones and their duals associated to an area metric geometry, and thus paves the ground for a discussion of the related local and global causal structures in standard fashion. In order to provide simple algebraic criteria for an area metric manifold to present a consistent spacetime structure, we develop a complete algebraic classification of area metric tensors up to general transformations of frame. This classification, valuable in its own right, is then employed to prove a theorem excluding the majority of algebraic classes of area metrics as viable spacetimes. Physically, these results classify and drastically restrict the viable constitutive tensors of non-dissipative linear optical media.